A SysOps Administrator is managing an application that runs on Amazon EC2 instances behind an Application Load Balancer. The instances run in an Auto Scaling group across multiple Availability Zones. The application stores data in an Amazon RDS MySQL DB instance. The Administrator must ensure that that application stays available if the database becomes unresponsive.
How can these requirements be met?

A. Create read replicas for the RDS database and use them in case of a database failure
B. Create a new RDS instance from the snapshot of the original RDS instance if a failure occurs
C. Keep a separate RDS database running and switch the endpoint in the web application if a failure occurs
D. Modify the RDS instance to be a Multi-AZ deployment