Which of the following statements is wrong about the test items of IEEE 1588V2 time protection function?

Which of the following statements is wrong about the test items of IEEE 1588V2 time protection function?
A . The active and standby states of the clock board and cross-connect board on the OptiX OSN 8800 are related to each other. When performing a switchover test, it is recommended to only switch the cross-connect board or the clock board.
B . The active and standby states of the clock board and cross-connect board on the OptiX OSN 6800 are related to each other. When performing a switchover test, it is recommended to only switch the cross-connect board or the clock board.
C . Test the long-term stability of the time performance in PTP synchronization mode. The output time performance should be within ±1us.
D . For the long-term jitter test of the physical layer synchronization mode, a time analyzer with a GPS receiver is used to observe at the node for more than 8 hours. The test output time performance should be within ±1us.

Answer: B