You have a setup in AWS which consists of EC2 Instances sitting behind and ELB. The launching and termination of the Instances are controlled via an Autoscaling Group. The architecture consists of a MySQL AWS RDS database. Which of the following can be used to induce one more step towards a self-healing architecture for this design?

Answer options:

A.Enable Read Replica`s for the AWS RDS database.
B.Enable Multi-AZ feature for the AWS RDS database.
C.Create one more ELB in another region for fault tolerance
D.Create one more Autoscaling Group in another region for fault tolerance

Answer – B
The AWS documentation mentions the following
Amazon RDS Multi-AZ deployments provide enhanced availability and durability for Database (DB) Instances, making them a natural fit for production database workloads. When you provision a Multi-AZ DB Instance, Amazon RDS automatically creates a primary DB Instance and synchronously replicates the data to a standby instance in a different Availability Zone (AZ). Each AZ runs on its own physically distinct, independent infrastructure, and is engineered to be highly reliable. In case of an infrastructure failure, Amazon RDS performs an automatic failover to the standby (or to a read replica in the case of Amazon Aurora), so that you can resume database operations as soon as the failover is complete. Since the endpoint for your DB Instance remains the same after a failover, your application can resume database operation without the need for manual administrative intervention.
For more information on AWS RDS Multi-AZ, please refer to the below link:
https://aws.amazon.com/rds/details/multi-az/