M2LA单元是无源器件，它通过接收信号？（）

A.Use Current Package
B.Erase SW and DB from Flash
C.Load DB MMI->BTS
D.Erase DB from Flash

A.X301
B.X1701
C.X31
D.X30

A.Rx CLOCK
B.None
C.Sync Input
D.Internal Timing