The primary line module has failed and the spare line module is nowactive.What occurs，by default，when the primary line module returns to an operational status？（）

A.The primary line module is inactive for five minutes and then becomes active.
B.The primary line module is in standby mode，while the spare line module remains active.
C.The primary line module becomes active immediately and the spare line module becomes inactive.
D.The primary and spare line modules are active for five minutes，after which time the spare line module becomes inactive.