Refer to the exhibit. R2 and R3 are running EBGP and are learning Network A and Network
B. R2 and R3 are also running IBGP to exchange Network A and Network
B. OSPF is IGP. R2 and R3 are advertising default routes. R1 and R4 can send and receive traffic from Network A and Network B respectively. However, Network A cannot send traffic to Network
B. How can you solve this problem? 

Answer options:

A. create a tunnel between R2 and R3
B. create a tunnel between R2 and R4
C. create static default routes pointing from R1 and R4 to R2 and R3, respectively
D. convert R3 and R2 to ABRs so that R1 and R4 can choose the closest ABR to exit the network

A