MPLS VPN providers can be vulnerable to denial of service attacks by customers generating too many routes and depletting resources in the PE router. Which are valid methods of combating this possibility?

A.
Limit the number of prefixes from a BGP neighbor using the neighbor maximum prefix command.

B.
Limit the number of routes that can be imported into a VRF using the maximum route command.

C.
Limit the size of the VRF routing table using the VRF maximum size command.

D.
Limit the number of BGP neighbors in the configuration.