If the switching SWE is the master node of sub-ring 2, which of the following can be known from the above information?

The figure shows the networking application of RRPP. The customer LAN switches SWA, SWB, SWC, and SWD form the RRPP ring main ring 1, and the switches SWB, SWC, and SWE form the sub-ring 2.

If the switching SWE is the master node of sub-ring 2, which of the following can be known from the above information?

A . If the link between switch SWA and switch SWB is down, switch SWE will release the secondary port
B . If the link between switch SWB and switch SWC is down, switch SWE will release the secondary port
C . If the link between switch SWA and switch SWB is down, and the link between switch SWB and switch SWC is down, switch SWE will release the secondary port.
D . If the link between switch SWA and switch SWB is down, and the link between switch SWA and switch SWD is down, switch SWE will release the secondary port.

Answer: C