Which one of the following controls the voltage produced at the output of the alternator?

A voltage regulator controls the voltage produced at the output of the alternator. It's a device that maintains the output voltage of an alternating current (AC) power source within a safe range. The voltage regulator compares the actual output voltage to the desired voltage level and adjusts the voltage accordingly.

Voltage Meter, Voltage Stabilizer, and Voltage Backup Device are not devices that control the voltage produced at the output of the alternator. They are different types of equipment and have different functions.

A voltage meter is a device used to measure the voltage in an electrical circuit. A voltage stabilizer is an electronic device that maintains a constant voltage level. A voltage backup device is a device that provides temporary backup power in case of an electrical outage.