A (S3 RTC) is required to meet the “replicated within 15 minutes” requirement in a verifiable way. Replication Time Control is the S3 feature that provides a 15-minute replication time SLA for replicated objects (instead of “best effort” replication timing).

B (S3 Multi-Region Access Point, active-passive) provides the most operationally efficient failover approach. An MRAP gives you a single global access point for S3 across Regions and supports controlled routing to the chosen bucket, avoiding custom DNS logic per application/client.

C (SubmitMultiRegionAccessPointRoutes) is the mechanism to perform failover for an MRAP by changing which Regional bucket is routed for the Multi-Region Access Point. This gives an explicit, API-driven “fail over now” action aligned with active-passive routing.

Why the others aren’t part of the “most operationally efficient” three:

D (Transfer Acceleration) optimizes upload/download performance over long distances , but it does not guarantee cross-Region replication within 15 minutes and doesn’t provide failover control.

E and F (Route 53 ARC) : ARC is great for controlling failover for endpoints behind routing controls, but for S3 bucket access the more direct and operationally simple approach is S3 Multi-Region Access Points with route updates via the S3 API. Using ARC here adds extra components/process compared to MRAP-native routing control.