正解:B
Comprehensive and Detailed In-Depth Explanation:
A Network Interface Card (NIC) is the hardware responsible for network connectivity. If the NIC is failing or underperforming (e.g., due to a bad driver, hardware fault, or misconfiguration), it can cause slow or unstable network speeds.
* Option A (CPU): A failing CPU affects overall system performance but not specifically network speed.
* Option C (HDD): A slow hard drive causes application lag, but not poor network performance.
* Option D (RAM): Affects multitasking and speed, not network throughput.
CompTIA A+ Core 1 Exam Objective Reference:
* Objective 3.5: Given a scenario, troubleshoot problems related to wired and wireless networks.