R1 and R2 are IS-IS Level 1 routers, but are not forming an adjacency.

Which two reasons would account for this happening? (Choose two.)

A.
The remote router is configured for both IPv4 and IPv6.

B.
The remote router does not have family iso enabled on its interface,

C.
The remote router does not have family clns enabled on its interface.

D.
The remote router is not configured to participate in the same Level 1 area

Explanation: