RAID 1 is a mirrored configuration that utilizes two drives and provides redundancy by allowing one drive to fail without data loss. This configuration meets the requirement of mirrored storage with two 4TB drives that support one failure. References: CompTIA A+ Certification Exam Guide, Ninth Edition, Chapter 8

Comprehensive and Detailed In-Depth Explanation:
Thermal printers create images using a heated print head on specially coated thermal paper. Vertical white lines indicate that part of the heating element is dirty or blocked, preventing heat transfer to the paper.
Cleaning the print head (heating element) will restore full functionality.
* Option A: Thermal printers do not use ink or toner, so this is not applicable.
* Option B: Wrong paper could cause blank output, but consistent vertical lines point to the print head.
* Option C: Maintenance kits are typically for laser printers, not thermal printers.
CompTIA A+ Core 1 Exam Objective Reference:
* Objective 3.7: Given a scenario, troubleshoot common printer problems.

The power supply unit (PSU) is the component that converts AC power from the outlet to DC power for the computer. If the PSU fails, the computer will not turn on. The CPU, RAM, and GPU are not directly related to the power supply and would not prevent the computer from turning on.

The BEST solution to mitigate spam that appears to come from an organization's own domain is to implement SPF (Sender Policy Framework). SPF is an email validation protocol designed to detect and prevent email spoofing, which is a common tactic used by spammers. By publishing SPF records in the organization's DNS (Domain Name System), the recipient's mail server can check if an incoming email originated from a valid source. If the email fails SPF authentication, it can be blocked or flagged as spam. Therefore, SPF helps to prevent email spoofing and mitigate the risk of spam coming from an organization's own domain

DSL (Digital Subscriber Line) uses POTS (Plain Old Telephone Service) lines to provide high-speed internet access. If the POTS lines are not working, it could cause an internet outage for DSL customers. Fiber and cable internet typically use different types of infrastructure, while satellite internet is not reliant on POTS lines. References: CompTIA A+ Certification Exam: Core 1 - Page 231