P4S-R2 and P4S-R3 Are Learning Network a and Network B

Multiple Choice

P4S-R2 and P4S-R3 are learning Network A and Network B through EBGP peering sessions as shown in the figure. P4S-R2 and P4S-R3 are also configured to peer by use of IBGP, and they are both advertising default routes through OSPF. Network A is not able to reach destinations on Network A; which step should be takes to solve this problem?

A) Create a tunnel between P4S-R2 and P4S-R3.
B) Create static default routes pointing from P4S-R1 and P4S-R4 to P4S-R2 and P4S-R3, respectively.
C) Convert P4S-R3 and P4S-R2 to ABRs so that P4S-R1 and P4S-R4 can choose the closest ABR to exit the network.
D) Create a tunnel between P4S-R2 and P4S-R4.