Which of the following statements about the 1+1 protection of cross-connect boards are correct? (Multiple Choice)

Which of the following statements about the 1+1 protection of cross-connect boards are correct? (Multiple Choice)
A . The source service board sends services to the active and standby cross-connect boards.
B . After service cross-connections are completed, the active and standby cross-connect boards send the data of the active cross-connect board to the sink service board.
C . The sink service board can receive only the data from the active cross-connect board.
D . The buses of the two cross-connect modules work independently and do not interfere with each other.
E . The dual-bus system structure indicates that the service board performs dual feeding of data to the cross-connect side and selective receiving of the data on the cross-connect side.
F . Two cross-connect boards have the same configuartion. Service boards will selectively receive services from one of them based on the quality of services and status of cross-connect boards.

Answer: ADEF