Click the Exhibit button.
If you have a fiber cut on all four fibers between nodes C and D in the following diagram put the events listed below in correct chronological sequence.

1. node A loops back traffic in the direction of node E
2. node D initiates a line switch and signals the fact in the K2 byte
3. node C loops back traffic in the direction of node B
4. both sides switch traffic to the protect channel and the circuit is restored in less than 50 ms
5. nodes C detects the loss of signal and signals the fact in the K1 byte

A.
1, 2, 5, 3, 4

B.
2, 1, 5, 3, 4

C.
5, 3, 1, 2, 4

D.
5, 3, 4, 1, 2