Network topology exhibit

What can prevent the corresponding BGP session from being successfully established?

A.
Domain 2 and Domain 5 cannot establish the IBGP session because Domain 2 and Domain 5 are not directly connected.

B.
Domain 1 and Domain 2 establish the EBGP session if the BGP holddown timers between the two EBGP neighbors are different.

C.
Domain 2 and Domain 5 cannot establish the IBGP session using the loopback0 interface if the EBGP-multihop value is set to the default value.

D.
Domain 1 and Domain 2 cannot establish the EBGP session using the loopback0 interface if the EBGP-multihop value is set to the default value.