What statement about DCC tunneling in the ONS 15454 is true?

A.
Only the first STS frame in any OC-n signal is used for tunneling.

B.
For security reasons, the 15454 randomly assigns an STS frame from within any OC-n signal to
be used for tunneling.

C.
A different STS frame is used on each section of the ring, to prevent overlap or conflict on the
protection path.

D.
Only the last STS frame in any OC-n signal is used for tunneling (this feature is also used as a
bit rate indicator).

Explanation: