Thermal printerscreate images using aheated print headon specially coated thermal paper. Vertical white lines indicate thatpart 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 donot 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 most likely cause of this issue is incorrect tray settings on the user's printer. According to CompTIA Core
1 (220-1201) printer configuration and troubleshooting concepts, printers rely on tray configuration settings to determine the paper size and paper type loaded in each tray. If the tray is not configured for 11 × 17 (Tabloid
/Ledger) paper, the printer will assume the required paper is unavailable-even if the paper is physically present.
When a print job specifies a paper size that does not match the tray's configured settings, the printer commonly displays a message prompting the user to insert the correct paper. The fact that the same document prints successfully on another printer of the same model confirms that the driver, permissions, and connectivity are functioning correctly, further isolating the issue to the local printer's tray configuration.
An incorrect driver would cause consistent problems across printers, not just one. Connectivity issues would prevent communication with the printer entirely, and insufficient permissions would generate access or authorization errors rather than a paper prompt.
CompTIA emphasizes verifying tray assignments and paper size configuration as a primary troubleshooting step when printers incorrectly request paper that is already loaded.
References:CompTIA A+ Core 1 (220-1201) Official Study Guide - Printer Configuration, Paper Handling, and Troubleshooting

A distorted image where the screen is not symmetrical (wider at the top or bottom) is typically due to keystone distortion. Adjusting the projector's keystone settings corrects this trapezoidal effect caused by an angled projection.
Reference: "CompTIA A+ Complete Study Guide" by Quentin Docter - Chapter 3, page 152.

The symptoms clearly point to a hardware-level signal degradation issue, which is most commonly caused by a malfunctioning or damaged Wi-Fi antenna in the smartphone. CompTIA A+ mobile device troubleshooting emphasizes comparing the affected device ' s signal strength with other nearby devices. In this case, other devices in the same location have stronger Wi-Fi signals, meaning the network itself is functioning normally.
The consistent low signal across multiple networks strongly suggests antenna failure.
Modern smartphones use internal antenna assemblies located along the frame or behind the back cover. If the antenna becomes loose, damaged, or obstructed, the device may show weak or unstable Wi-Fi connectivity, especially in crowded environments where strong, stable reception is required to maintain a connection.
Option B (outdated Wi-Fi standard) would limit speed but not cause significant signal weakness compared to surrounding devices. Option C (interference) affects all devices in an area similarly-not just one device.
Option D (power settings) may reduce background activity or scanning frequency, but it does not cause consistently low signal strength.
Therefore, the most likely cause is a malfunctioning Wi-Fi antenna inside the smartphone.

Fiber is the best option when the goal is the fastest possible network speeds between nearby locations. In CompTIA A+ Core 1 networking, fiber-optic cabling (single-mode or multimode) provides the highest bandwidth capacity and supports very high data rates over longer distances compared with copper media.
Fiber is also highly resistant to electromagnetic interference (EMI) because it transmits data as light rather than electrical signals, which improves reliability and signal quality-especially in environments with motors, fluorescent lighting, or other sources of interference. For nearby locations (such as buildings on the same campus), fiber is commonly used for backbone links and uplinks between switches because it delivers excellent throughput and can scale to higher speeds as equipment is upgraded.
DSL is limited by telephone-line quality and distance from the provider's equipment, and it is typically much slower than fiber. Satellite has higher latency and is not chosen when maximum speed and low delay are required. Coaxial can support broadband and some high-speed links, but it generally offers less bandwidth, more susceptibility to noise than fiber, and is not the top choice for highest-speed interconnection when fiber is available.