STM-16信号可以由（）个STM-4复用而来。

A.155Mbit/s
B.622Mbit/s
C.2.5Gbit/s
D.10Gbit/s

A.Usinωt+Vcosωt
B.Usinωt-Vcosωt
C.Usinωt±Vcosωt
D.Usinωt×Vcosωt

A.10^-2
B.10^-3
C.10^-4
D.10^-6