【单选题】You are paralleling two alternators and the pointer of the synchroscope slowly stops rotating and remains stopped in one position before the circuit breaker is closed. This would indicate ____.
A.
the synchronoscope is not functioning properly and should be checked
B.
the voltage of the incoming alternator is the same as that of the main switchboard
C.
the incoming alternator is in phase with the switchboard, but the frequency is not the same
D.
the frequency of the incoming alternator is the same as that of the main switchboard