After the recent implementation of a new design that incorporated GRE tunnels into the network, the network operations staff is seeing the following syslog message in multiple routers on the network – %TUN-5-RECURDOWN: Tunnel0 temporarily disabled due to recursive routing. From a design perspective, what was not taken into account prior to implementing the solution?
A . The neighboring routers cannot respond within the specified hold time.
B . The interface on the router that is the source of the tunnel is down.
C . The interface on the neighboring router that is the source of the tunnel is down.
D . The router is learning the route to the tunnel destination address using the tunnel interface.
E . The tunnel interface on the router is not receiving any keepalives within the specified hold time.
Answer: D