Which of the following would block access to an untagged port when connected to a Layer 2 device?

The corporate head office has assigned the subnet of 10.1.100.0/24 to a network technician. The technician wants to create subnets for the finance department, human resources, and IT. Given the following device counts:
Finance: 70 devices
Human resources: 38 devices
IT: 16 devices
Which of the following outlines how the technician should allocate the address space given?

A network engineer configured new Firewalls with the correct configuration to be deployed to each remote branch. Unneeded services were disabled, and all firewall rules were applied successfully. Which of the following should the network engineer perform NEXT to ensure all the firewalls are hardened successfully?

An administrator recently implemented new SOHO routers for a company's teleworking employees. Before deploying the routers, the administrator changed the default credentials and disabled unnecessary services. Within a few days of deployment, hackers gained access to the routers. Which of the following is the MOST important thing the administrator forgot to do?

A technician has been asked to diagnose problems with DHCP addressing on a VLAN. The DHCP server responds to pings from the technician's machine. Which of the following should the technician use to help diagnose the problem?