Which solution will meet this requirement?
Increase the RDS instance size.
Modify the RDS cluster to run in a single Availability Zone.
Create a read replica in another AWS Region. Promote the read replica in case of failure.
Create an RDS proxy. Point the application to the proxy endpoint.
Explanations:
Increasing the RDS instance size may improve performance, but it does not directly address reducing failover time. Failover time is more related to the architecture and configuration of the database.
Running the RDS cluster in a single Availability Zone would reduce high availability and resilience, which is contrary to the goal of decreasing failover time in a multi-AZ setup.
Creating a read replica in another AWS Region introduces cross-region latency, which would actually increase failover time rather than reduce it.
Creating an RDS Proxy helps improve failover time by pooling and managing connections to the database. This reduces the time it takes for the application to re-establish connections during a failover.