https://intellinetnetwork.eu/pages/what-is-a-poe-injector
The quickest way to resolve the issue is to install a Power over Ethernet (PoE) injector to provide power to the IP phone. An unmanaged switch does not provide PoE, so an injector is needed to power the phone.

The issue of video but no audio on a projector in a conference room can be resolved by utilizing an HDMI connection between the PC and the projector. HDMI supports both video and audio signals and is commonly used to connect a PC to a projector for presentations. Changing the input on the projector to VGA, changing the output on the PC to DVI, or modifying the projector's refresh rate will not resolve the issue. References:
CompTIA A+ Certification Exam: Core 1 - Objective 2.5

If the printer uses a dynamic IP address and has been without power, the DHCP lease may have expired, and the printer may have been assigned a new IP address. Devices attempting to connect using the old IP address will fail.
* Why Not A (The printer has a static IP address): A static IP address would remain unchanged, so this would not cause the issue.
* Why Not C (The printer has an APIPA): APIPA (Automatic Private IP Addressing) would occur only if the printer cannot contact the DHCP server, but this isn't described in the scenario.
* Why Not D (The printer has a public IP address): A public IP address is irrelevant in a local network scenario.
CompTIA A+ Exam Reference: Core 1 (220-1101), Section 2.6, IP address management.

The correct answer is B. 802.11ax.
802.11ax, also known as Wi-Fi 6 or Wi-Fi 6E, is the latest wireless standard that can operate in the 6GHz frequency range. This standard was approved by the IEEE in February 2021 and offers higher throughput, lower latency, and improved efficiency compared to previous standards1 The 6GHz frequency range spans from 5.925 GHz to 7.125 GHz and provides 1200 MHz of additional spectrum for Wi-Fi devices. This means that Wi-Fi 6E can support more channels, wider bandwidths, and less interference than the existing 2.4 GHz and 5 GHz bands. Wi-Fi 6E can access up to 59 20-MHz channels, 29
40-MHz channels, 14 80-MHz channels, or 7 160-MHz channels in the 6GHz band1
802.11ac, also known as Wi-Fi 5, is the previous wireless standard that can only operate in the 5GHz frequency range. It was approved by the IEEE in December 2013 and offers faster speeds and better performance than older standards. However, it cannot use the new spectrum in the 6GHz band and has limited channel availability and capacity in the crowded 5GHz band2
802.11g and 802.11n are older wireless standards that can only operate in the 2.4GHz frequency range. They were approved by the IEEE in June 2003 and October 2009, respectively, and offer lower speeds and performance than newer standards. They also suffer from more interference and congestion in the saturated 2.4 GHz band, which is shared by many other devices and technologies32

Explanation: