Explanation
A directional antenna is a type of antenna that radiates or receives radio waves in a specific direction. This can help limit wireless access outside the building by focusing the signal towards the intended area and reducing the signal strength in other directions. A private VLAN is a feature that isolates network devices within a VLAN. Disabling roaming on the WAP prevents wireless clients from switching to another WAP when the signal is weak. Stopping broadcasting of the SSID hides the network name from wireless clients, but does not prevent them from connecting if they know the SSID.
References: CompTIA Network+ Certification Exam Objectives Version 7.0 (N10-007), Objective 3.1: Given a scenario, install and configure wireless LAN infrastructure and implement the appropriate technologies in support of wireless capable devices.

The switchport is shut down, which means it is administratively disabled and cannot forward traffic. The image shows that the switchport status is "down" and the protocol status is "down", indicating that there is no physical or logical connection. The cable is plugged in, as shown by the "connected" message under the interface name. The loopback is not set, as shown by the "loopback not set" message under the encapsulation type. The bandwidth configuration is correct, as shown by the "BW 10000 Kbit/sec" message under the MTU size. References: [CompTIA Network+ Certification Exam Objectives], Domain 3.0 Infrastructure, Objective
3.1: Given a scenario, use appropriate networking tools, Subobjective: Command line tools (ping, netstat, tracert, etc.)

A POE injector is a device that provides power and data over a single Ethernet cable to a POE device, such as a VoIP phone, a wireless access point, or a security camera12.
A POE injector is needed when the switch or router that connects to the POE device does not support POE or does not have enough POE ports available12.
A POE injector can be installed between the switch or router and the POE device, using two Ethernet cables: one from the switch or router to the injector, and another from the injector to the POE device12.
A POE injector can supply up to 30W of power per port, depending on the POE standard it supports (802.3af or 802.3at)12.
B . Enable MDIX is not a correct answer because MDIX is a feature that allows a switch or router to automatically detect the type of cable (straight-through or crossover) and adjust the pin assignments accordingly34.
MDIX is not related to providing power to a POE device, and it is usually enabled by default on modern switches and routers34.
C . Use a crossover cable is not a correct answer because a crossover cable is a type of Ethernet cable that swaps the transmit and receive pairs of wires, allowing two devices of the same type (such as two switches or two computers) to communicate directly56.
A crossover cable is not needed to connect a VoIP phone to a switch or router, as they are different types of devices that use different pin assignments56.
A crossover cable also does not provide power to a POE device, and it may not work with gigabit Ethernet or auto-MDIX devices56.
D . Reconfigure the port is not a correct answer because reconfiguring the port on the switch or router that connects to the VoIP phone does not address the issue of providing power to the phone78.
Reconfiguring the port may involve changing the speed, duplex, VLAN, or security settings, but none of these affect the power delivery to the POE device78.
Reconfiguring the port may also cause network connectivity or performance issues if the settings are not compatible with the VoIP phone or the network78.
Reference:
What Is a PoE Injector and How to Use It? | FS Community
Power Injector for PoE Networks | Eaton
CCNA / CCENT / Network+ Tutorial: Crossover Cables And Auto MDI-X
Straight-Through and Crossover Cables - N10-008 CompTIA Network+ : 2.3
Straight-Through, Crossover, and Rollover Cables - CompTIA Network+ N10-006 - 1.5 CompTIA Network+ Cheat Sheet (Updated for Latest Exam) - StationX CompTIA Network+ : Common TCP And UDP Default Ports - Tutorialsweb.Com A Guide to Network Troubleshooting - CompTIA

Spanning tree protocol(STP) is a layer 2 network protocol used to prevent looping within a Network topology. STP was created to avoid the problems that arise from computers exchanging data on a local area network that contains redundant paths.

If a network client is trying to connect to the wrong TCP port, the most likely response it would receive is a RST (reset) packet from the server. A RST packet is used to terminate a TCP connection abruptly, either because the server does not recognize the port number, or because the server has no application listening on that port, or because the server detects an error or an attack on the connection. A RST packet tells the client to stop sending any more data and close the connection immediately12 The other options are not as likely to be the responses for connecting to the wrong TCP port. A FIN (finish) packet is used to gracefully end a TCP connection, after both parties have exchanged all the data they need. A FIN packet indicates that the sender has no more data to send and is ready to close the connection. A FIN packet does not imply an error or a rejection, but rather a normal termination of the connection12 An ICMP (Internet Control Message Protocol) Time Exceeded message is used to inform the sender that a packet has been discarded because its time to live (TTL) value has reached zero. A TTL value is a counter that decrements by one every time a packet passes through a router. When the TTL value reaches zero, the packet is dropped and an ICMP Time Exceeded message is sent back to the sender. This message is used to prevent packets from looping endlessly in the network, and also to implement the traceroute tool, which shows the path and the hops that a packet takes to reach a destination. An ICMP Time Exceeded message is not related to the TCP port number, but rather to the IP routing and the TTL value3 A Redirect message is another type of ICMP message that is used to inform the sender that there is a better route to the destination. A Redirect message is sent by a router when it receives a packet from a host on the same network, and forwards the packet to another router on the same network. A Redirect message tells the sender to use the second router as the next hop, instead of the first router, to optimize the routing and avoid unnecessary hops. A Redirect message is also not related to the TCP port number, but rather to the IP routing and the network topology3 References:
* What causes a TCP/IP reset (RST) flag to be sent?
* RFC 792: Internet Control Message Protocol