Cascade Regional Airlines runs its booking site primarily out of its East US region, with a fully provisioned but idle standby deployment in West US 2 meant only to take over if East US becomes completely unavailable. Which Traffic Manager routing method should route all traffic to East US under normal conditions and only shift to West US 2 during an outage?

Priority routing in Traffic Manager lets an administrator rank endpoints and directs all traffic to the highest-priority healthy endpoint, only shifting to the next endpoint in the priority order if the current one fails its health checks — which is exactly the active/passive, hot-standby behavior described for East US and West US 2. Weighted routing instead distributes a proportional percentage of traffic across multiple endpoints simultaneously based on assigned weights, which would send some live traffic to the idle West US 2 deployment even while East US is healthy, contradicting the requirement. Performance routing sends each user to whichever endpoint gives the lowest network latency from their location, which again would actively split traffic between regions rather than keeping West US 2 fully idle. Geographic routing directs users to specific endpoints based on the geographic origin of their DNS query, which is meant for data-sovereignty or content-localization scenarios, not failover. The exam-relevant caveat: Traffic Manager failover depends entirely on its own endpoint health checks and on DNS TTL expiry propagating to resolvers, so failover is not instantaneous and a low TTL is important for faster recovery. To verify the setup, review the profile's routing method in the portal, confirm it reads Priority, and confirm East US carries the lower priority value. In Traffic Manager the lower number wins, so the active endpoint should sit at priority 1 and the West US 2 standby at 2.