Refer to the exhibit. A customer experienced an unexpected network outage when the link between R1 and R2 went down. An architect must design a solution to ensure network continuity in the event the…

Making R3 an L1L2 router allows it to act as both an Area 0 (L2) and Area 1 (L1) router. If the primary link between R1 and R2 fails, R3 can then forward traffic between Area 0 and Area 1, ensuring network continuity and redundancy. This is a common design pattern for IS-IS multi-area networks to create backup paths.

Making R31 an L1 router would restrict its routing capabilities to within Area 1 only, preventing it from routing traffic to Area 0 and thus not providing a backup path across areas.

Making Area 0 L2-only is not a standard or beneficial IS-IS configuration for redundancy, and Area 0 is typically the backbone area, often containing L2 routers.

Making R11 an L2 router would not solve the problem of a failed R1-R2 link, as R11 is already in Area 0 and would still need a path to Area 1.