Your customer has enabled IPv6 and IPv4 on routers R1 and R2, both running ISIS routing protocol, and they can no longer reach R3 network 172.26.15.0/24 (R3 does not enable IPv6, enables IPv4 only).

Which two steps should be taken no restore reachability to R3? (Choose Two.)

A.
Enable wide metrics.

B.
Enable OSPFv3 to support IPv4 and IPv6 simultaneously.

C.
Configure static routes to all unreachable networks and redistribute to IS-IS.

D.
Transition to IS-IS Multiple Topology Mode on R1 and R2.

E.
Transition to IS-IS Multiple Topology Mode on R3.

F.
Create an IPv6 tunnel from R2 to R3.