You are installing a Cisco ONS 15454 SDH in a service provider site. An E3 cable is being connected to a digital cross-connect system. 
What is the maximum distance allowed between the two？（）

A. An equal amount of working and protect bandwidth is required.
B. DCC bandwidth is not large enough to handle K1/K2 processing.
C. Switch times would exceed 50 ms for an STM-1 MS-SPRing ring.
D. There is not enough bandwidth in an STM-1 ring to justify MS-SPRing protection.

A. 0
B. 1
C. 2
D. 3
E. 5