Which statement is correct regarding GRE tunnel endpoints when you are configuring GRE over
IPsec?

A.
The tunnel interfaces of both endpoints must be in the same IP subnet.

B.
A mirror image of the IPsec crypto ACL needs to be configured to permit the interesting end-user traffic between the GRE endpoints.

C.
The tunnel interfaces of both endpoints should be configured to use the outside IP address of
the router as the unnumbered IP address.

D.
For high availability, the GRE tunnel interface should be configured with a primary and a
backup tunnel destination IP address.