How should the concept of mobility domains and mobility groups be explained to a customer?

How should the concept of mobility domains and mobility groups be explained to a customer?
A . WLCs do not need to be in the same mobility domain to communicate with each other Mobility groups constrain the distribution of security context of a client and also constrain AP fail-over between controllers.
B . A mobility group does not constrain the distribution of security context of a client and also does not constrain AP fail-over between controllers when the WLCs are in the same mobility domain.
C . if WLCs are in same mobility domain, they communicate with each other. Mobility groups constrain the distribution of security context of a client and also constrain AP fail-over between controllers.
D . If WLCs are in the same mobility domain, they communicate with each other but. if an anchor WLC ® present, it must: be in the same mobility domain for communication to be possible.

Answer: C