When paralleling two alternators the synchronizing lamps grow dim and are totally darkened as the synchroscope pointer approaches the 0° position. What does this indicate?

Correct Answer: Option B — the incoming alternator is in synchronism with the bus

Dark synchronizing lamps and a synchroscope pointer at zero degrees indicate that voltage magnitudes, phase angles, and frequencies of the incoming alternator match the bus perfectly, allowing safe breaker closure per IEEE 45 synchronization guidelines.