In the following exhibit, Router A will not form an adjacency with Router B. What is the problem?

A. The hello/dead timer does not match.
B. There is no designated router on the network.
C. The process IDs do not match.
D. The area IDs do not match.

D. In order to form an adjacency, the area IDs must match. In this exhibit, Router A has an area of 0 and Router B has an area of 1 configured.