正解:B
One of the possible causes of slow OS performance, random shutdowns, and loud fan noise is the CPU overheating. This can happen due to dust accumulation, faulty cooling system, or high CPU usage. Overheating can damage the CPU and other components, so it is important to monitor the CPU temperature and take preventive measures.
Reference:
The Official CompTIA A+ Core 1 Student Guide (Exam 220-1101) eBook1, page 2-9, section "CPU Cooling Methods".
The Official CompTIA A+ Core 1 (220-1101) Certification Study Guide2, page 2-11, section "Troubleshooting CPUs".