Testing for the proper supply __________ is usually the first step when troubleshooting a circuit.
If __________ is not present at the switching location of overhead lighting, at the line terminals of the motor-starter contactor, or between the vertical buses of the control circuit (blown fuse, open disconnect, and the like), or if the __________ is too high or too low, the __________ problem must be corrected before further investigation of the problem is fruitful.
A) current; voltage; current; voltage
B) voltage; current; voltage; current
C) voltage; voltage; voltage; voltage
D) current; current; current; current
Share your understanding of this question with the correct explanation.