A critical application runs on a single EC2 instance and uses an ElastiCache for Redis single-node cluster plus an RDS for MariaDB DB instance. Every component must be healthy and active for the application to function. You need to redesign so the infrastructure can automatically recover from failures with minimal downtime. Which combination of changes should you implement? (Choose three.)

The current architecture has single points of failure for the application, database, and cache. To achieve automatic recovery and minimal downtime: 1. Application Tier: Placing EC2 instances behind an Elastic Load Balancer (ELB) and using an Auto Scaling group with a minimum capacity of two instances ensures that if one instance fails, the ELB routes traffic to the healthy instance, and Auto Scaling replaces the failed one. This provides high availability and fault tolerance. 2. Database Tier: Modifying the RDS MariaDB instance to a Multi-AZ deployment automatically provisions a synchronous standby replica in a different Availability Zone. In case of a primary DB instance failure or AZ outage, RDS automatically fails over to the standby, minimizing downtime without manual intervention. Creating a read replica in the same AZ does not provide cross-AZ fault tolerance, and promoting it would be a manual process. 3. Cache Tier: Creating a replication group for ElastiCache for Redis and enabling Multi-AZ provides high availability. The replication group consists of a primary node and one or more read replicas across different AZs. If the primary fails, ElastiCache automatically promotes a replica to primary, ensuring continuous operation. ElastiCache for Redis does not integrate with EC2 Auto Scaling groups for managing its nodes.