Refer to the exhibit. All switches must be part of a common MST region. On the basis of the information presented in the exhibit, which statement is true?

A.
The configuration must be implemented on the MST root switch only.

B.
The configuration is optional on the MST root switch.

C.
The configuration is mandatory on all MST switches in the MST region.

D.
The configuration is optional on all MST switches in the MST region.