You are designing a network using multipoint GRE tunnels and need to be able to detect when connectivity between the GRE tunnel endpoints is broken. Which statement is true about configuring…

Timer value matching is a requirement for point-to-point GRE keepalives only; the fundamental problem with mGRE is that keepalives are unsupported entirely, not a configuration mismatch.

Mutual keepalive support is relevant for point-to-point GRE tunnels, not mGRE, where the feature does not function regardless of both routers supporting it.

There is no configuration option that enables keepalive-based failure detection on mGRE tunnels; the technology itself does not support the mechanism.

Multipoint GRE tunnels have no fixed single remote endpoint, so the keepalive mechanism - which works by sending packets to a specific destination and expecting a reply - is architecturally incompatible with mGRE; failure detection in mGRE environments must rely on NHRP or routing protocol hello/dead timers instead.