单项选择题
A.2Mbps→C12→VC12→TU12→TUG2→VC3→AU3→AUG→STM-N
B.2Mbps→C12→VC12→TU12→TUG2→TUG3→AU3→AUG→STM-N
C.2Mbps→C12→VC12→TU12→TUG2→TUG3→VC4→STM-N
D.2Mbps→C12→VC12→TU12→TUG2→TUG3→VC4→AU4→AUG→STM-N
E.2Mbps→C11→VC11→TU11→TUG2→TUG3→VC4→AU4→AUG→STM-N