Amazon Route 53 health checks can automatically perform DNS failover to healthy endpoints. When integrated with an Application Load Balancer, this provides a highly resilient system architecture that automatically routes traffic to healthy resources across Regions or endpoints.

From AWS Documentation:

“Route 53 DNS failover automatically routes traffic away from unhealthy resources and directs it to healthy resources that you specify in DNS records.”

(Source: Amazon Route 53 Developer Guide – DNS Failover)

Why B is correct:

Route 53 health checks automatically monitor endpoint health and switch to a healthy target when the primary endpoint fails.

The failover process is automatic, with no manual updates to DNS records required.

Combined with ALB’s built-in multi-AZ resilience, this provides maximum availability.

Why others are incorrect:

A & C: Require manual DNS updates, which are not automatic and introduce latency.

D: Creating new ALBs during failover increases downtime and is operationally inefficient.