Explanation
A hypervisor is a software layer that manages and allocates resources for virtual machines (VMs) on a physical host machine. A technician can use a hypervisor to adjust the resource allocation for a virtual workstation, such as increasing the amount of RAM assigned to it from the available pool of memory on the host machine. This can improve the performance and functionality of the virtual workstation without requiring any hardware changes or modifications. Reference:
https://www.comptia.org/training/books/a-core-1-220-1101-study-guide (page 59)

The most likely answer is C. The pen batteries need recharging.
An active touch pen is a stylus that uses a battery to power features such as pressure sensitivity, buttons, or Bluetooth connectivity. If the pen batteries are low or depleted, the pen may stop working or become inaccurate1. To fix this issue, you should recharge the pen batteries using the provided charger or cable, or replace them with new ones if they are not rechargeable1.
The other options are less likely to cause the issue. A scratched tablet screen may affect the touch sensitivity, but it should not affect the pen functionality. The pen software may need updating to improve performance or compatibility, but it should not stop the pen from working altogether. Software updates may disable the pen if they change the settings or drivers, but this can be fixed by re-enabling the pen or reinstalling the drivers2.
References:
1: Troubleshoot your Surface Pen - Microsoft Support
2: Windows 10 touch screen: active pen works, finger does not - Super User

To increase the volume on a laptop using only a keyboard, a user can press and hold down the Fn key while pressing one of the function keys (usually F1-F12) that has an icon representing volume up.

Explanation
A crimper is a tool that is used to crimp (attach) an RJ45 connector onto the end of a patch cable. The crimper applies pressure to the connector to make a permanent connection between the connector and the cable, ensuring that the connector will stay attached to the cable.
A cable tester is used to test the connectivity of a network cable. A punchdown tool is used to terminate network cables in a patch panel or keystone jack. A loopback plug is a diagnostic tool that is used to test network interfaces by simulating network traffic.

Liquid cooling is an effective solution for managing the high heat output that can result from overclocking a GPU. It's more efficient than air cooling methods (like larger heat sinks or fan upgrades) and can better maintain lower temperatures under load, reducing the risk of overheating.
References:
* CompTIA A+ Core 1 Exam Objectives Section 3.4: Given a scenario, install and configure motherboards, CPUs, and add-on cards.
These answers align with the CompTIA A+ certification objectives and are derived from the official CompTIA A+ Core 1 (220-1101) and Core 2 (220-1102) Exam Objectives documents.