As show in the figure, which of the following statements is true?

A . R1 and R2 can establish adjacency, but cannot complete routing calculations
B . R1 and R2 can establish adjacency and can complete routing calculations
C . R1 and 2 cannot establish adjacency, because the network type of the interface is not consistent
D . R1 and R2 cannot establish adjacency, because OSPF process ID is not consistent

Answer: A