Explanation
The most efficient subnet address for a network that will have no more than 30 available IP addresses is
255.255.255.224. This subnet mask corresponds to a /27 prefix length, which means that 27 bits are used for the network portion and 5 bits are used for the host portion of an IP address. With 5 bits for hosts, there are
2^5 - 2 = 30 possible host addresses per subnet, which meets the requirement. The other options are either too large or too small for the network size. Reference: https://www.ibm.com/cloud/learn/subnet-mask

When selecting a RAID level, both redundancy and storage efficiency must be considered:
* RAID 1 mirrors data, providing high redundancy but reducing available storage to 50%. With eight drives, only four drives' worth of space would be available.
* RAID 5 uses striping with distributed parity. It provides good storage efficiency (n-1) but can only tolerate one drive failure.
* RAID 6 is similar to RAID 5 but uses dual parity, allowing two drives to fail while still maintaining data integrity. However, it reduces available storage to (n-2).
* RAID 10 (also known as RAID 1+0) combines mirroring and striping. It provides excellent redundancy and performance, allowing multiple drive failures as long as they aren't in the same mirrored pair.
Storage efficiency is 50%, but the redundancy and performance benefits outweigh this trade-off in high- availability environments.
Since the technician requires both maximum redundancy and high available storage, RAID 10 is the best choice.
Reference: CompTIA Server+ SK0-005 Official Textbook, Chapter 5 - Storage Solutions and RAID

Bollards are an example of a method that is used to prevent motor vehicles from getting too close to building entrances and exits. Bollards are short, sturdy posts that are installed on sidewalks, parking lots, or roads to create physical barriers and control traffic flow. Bollards can be used to protect pedestrians, buildings, or other structures from vehicle collisions or attacks. Bollards can be made of various materials, such as metal, concrete, or plastic, and can be fixed, removable, or retractable.
Reference: https://en.wikipedia.org/wiki/Bollard

A blade server is a type of server that is installed in a chassis or an enclosure that provides power, cooling, networking, and management features. The blade server does not have any cables attached to it, as it connects to the chassis through a midplane or a backplane. A blade server can save space, energy, and cost compared to other types of servers. Verified Reference: [Blade server], [Chassis]