Explanation
SODIMM stands for Small Outline Dual In-line Memory Module and is a type of memory module that is compatible with laptops and other small devices. SODIMMs are smaller and thinner than DIMMs (Dual In-line Memory Modules), which are typically used for desktop PCs and servers. Upgrading or adding SODIMMs can increase the amount of RAM available for a laptop, which can improve its performance and speed when running process-intensive tasks. Reference:
https://partners.comptia.org/docs/default-source/resources/a-core-series-combined-content-guide (page 24)

Explanation
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

Explanation
The domain name system (DNS) is the component that houses the MX record. The MX record is a type of DNS record that specifies which mail server is responsible for receiving email messages for a domain name.
VLAN is an acronym for virtual local area network, which is a logical subdivision of a network that allows devices to communicate as if they were on the same physical segment. DHCP is an acronym for dynamic host configuration protocol, which is a network protocol that assigns IP addresses and other configuration parameters to devices on a network automatically. SMTP is an acronym for simple mail transfer protocol, which is a network protocol that allows sending and receiving email messages over TCP/IP networks

Explanation
A web server is a software application that serves HTTP (Hypertext Transfer Protocol) requests by delivering web pages and other files to users' web browsers. The main function of a web server is to host home pages and business portals, making them accessible to users via the internet. References: CompTIA A+ Certification Exam Objectives 220-1001 - Networking - 1.6

Explanation
802.11ac is the 802.11 standard that supports both 5GHz and 2.4GHz channel frequencies. 802.11ac is the latest wireless networking standard that operates in both the 5GHz and 2.4GHz frequency bands. It provides higher wireless network speeds and better reliability compared to previous standards, such as 802.11a,
802.11b, and 802.11g. The 802.11a standard operates exclusively in the 5GHz band, while the 802.11b and
802.11g standards operate exclusively in the 2.4GHz band.