C: Installing redundant PSUs (Power Supply Units):
Redundant PSUs provide fault tolerance by ensuring that if one power supply fails, another will take over seamlessly.
This is a cost-effective way to increase uptime while waiting for the UPSs to arrive.
Incorrect Options:
A: Purchasing backup generators: Generators are costly and are typically used for long-term outages, not as an immediate or cost-effective solution.
B: Increasing input voltage: This is not a practical solution to hardware failures or power issues.
D: Activating a hot site: A hot site is an expensive, fully operational backup facility that would not be a cost- effective solution for this scenario.
Key Takeaway: Installing redundant PSUs is a cost-effective way to balance uptime requirements in case of power or hardware failure.
Reference: CompTIA A+ Core 1 Exam Objectives (220-1101), Domain 5.3 - Power-related troubleshooting.

The most likely cause of the issue is that the user's USB-C hub is faulty or incompatible with the laptop. The USB-C hub is a device that allows the user to connect multiple peripherals to the laptop using a single USB-C port. If the hub is not working properly, it may prevent the monitor, keyboard, mouse, and headset from functioning. The technician should replace the user's USB-C hub with a new one that is compatible with the laptop and test the peripherals again. Verifying the AC adapter voltage will not help with the issue, as the AC adapter is used to power the laptop, not the peripherals. Repairing the operating system will not help either, as the issue is not related to software. Reinstalling the drivers for affected devices may not help, as the issue may be caused by the hub, not the devices. Making sure the printer is not drawing too much power is irrelevant, as the printer is not connected to the hub or affecting the other peripherals. References: https://www.comptia.org
/blog/what-is-usb-c

An IP address beginning with 169.254 indicates that the device has not received a valid IP from the DHCP server. Rebooting the router can resolve minor configuration or network glitches, allowing DHCP to function correctly. The other options, such as adjusting lease time or static IP addresses, do not address the core problem. CompTIA A+ Core 1 objectives emphasize DHCP troubleshooting in SOHO networks.

The answer is C. Clean the air filter.
A flashing LED code on a projector usually indicates a problem with the projector's hardware, such as the lamp, the fan, the temperature sensor, or the air filter. According to the web search results, some possible causes and solutions for this problem are:
* Projector is too hot: Make sure that the vents and air filter are not clogged with dust or obstructed by nearby objects. Clean or replace the air filter. Make sure the environmental temperature is not too hot12.
* Projector has overheated and turned off: Leave it turned off to cool down for five minutes. Make sure that the vents and air filter are not clogged with dust or obstructed by nearby objects. Clean or replace the air filter. If operating the projector at high altitude, turn on High Altitude Mode12.
* Low air flow through the projector or air filter: Make sure that the vents and air filter are not clogged with dust or obstructed by nearby objects. Clean or replace the air filter12.
References:
* Projector Light Status
* Projector Light Status