The routers R1 and R2 need to have the same autonomous system (AS) number to form an EIGRP adjacency. In the exhibit, both routers are shown in the same AS, AS 100, which is consistent with the configuration requirement for EIGRP. Thus, ensuring that both routers are configured with the same AS number is the correct action to resolve the adjacency issue, as a mismatch in AS numbers will prevent EIGRP neighbors from forming.