Refer to the exhibit.
An engineer has set up a GRE tunnel between Router A and Router C. Router A can reach the Router C Loopback 1 interface but the tunneled traffic is not working. What is the cause of this issue?
A. Router A does not have a route to 4.4.4.4
B. Router B has a routing problem.
C. Router C does not have a route to 1.1.1.1
D. Router C has the wrong tunnel MTU
