You are an IT technician for your company. One of your employees has a computer that continually reboots when it is powered on. He has asked you to fix it. You suspect that the power supply may be failing. Which of the following is the BEST way to determine whether the power supply is causing the reboots a. Replace the power supply.
b. Listen for POST code beeps to determine the error's cause
c. Verify that the fan on the power supply is spinning
d. Use a multimeter to the power supply.

The BEST way to determine whether the power supply is causing the reboots is to:

d. Use a multimeter to the power supply.

Explanation:

The multimeter is an indispensable electronic measuring instrument that combines several measurement functions in one device.  It measures electrical voltage, current, and resistance at the same time.  There are analog and digital multimeters.  The analog multimeters have moving pointers to display their readings.   These days, the digital multimeter has proved to be an indispensable tool for testing, diagnosing, and troubleshooting electrical circuits, components, and devices.

(because i need 20 chars)