You have configured a GRE tunnel between two remote sites. This tunnel will be used to pass
traffic using RFC 1918 addressing over the Internet. You have verified that the tunnel interface is
up on both endpoints and see the output shown below:
user@router> show interfaces gr-0/0/0.0 terse
Interface Admin Link Proto Local Remote
gr-0/0/0.0 up up
Traffic between the remote sites is not being passed over this tunnel.
Which action would resolve this problem?

A.
You must use an IP-IP tunnel to support traffic using RFC 1918 addressing.

B.
You must use NAT to translate the private addresses to a public address.

C.
You must enable path MTU to ensure packets are properly fragmented.

D.
You must enable the inet protocol family on the GRE interfaces.