What is the best way to monitor system temperature?

A computer is randomly freezing, and you suspect that it might be overheating. What’s the best way to monitor the system temperature?

A) Buy a thermostat and mount it inside of the computer.

B) Place a thermostat in the path of the outgoing airflow.

C) Use a software utility to monitor the temperature of the system components.

D) Place the system into an air-tight box and use a thermometer to monitor the changes in heat over time.