Your company is planning to set up a WordPress application. The WordPress application will connect to a MySQL database. Part of the requirement is to ensure that the database environment is fault-tolerant and highly available. Which of the following options can help to fulfill this requirement? 

Answer options:

A.Create a MySQL RDS environment with the Multi-AZ feature enabled.
B.Create a MySQL RDS environment and create a Read Replica.
C.Create multiple EC2 instances in the same AZ. Host MySQL and enable replication via scripts between the instances.
D.Create multiple EC2 instances in separate AZ’s. Host MySQL and enable replication via scripts between the instances.

Answer – A
One way to ensure high availability and fault-tolerant environments is to ensure Instances are located across multiple availability zones. Hence, if you are hosting MySQL yourself, ensure that you have instances spread across multiple AZ’s.
The AWS Documentation mentions the following about the multi-AZ feature.
Amazon RDS provides high availability and failover support for DB instances using Multi-AZ deployments. Amazon RDS uses several different technologies to provide failover support. Multi-AZ deployments for Oracle, PostgreSQL, MySQL, and MariaDB DB instances use Amazon`s failover technology.
For more information on AWS Multi-AZ deployments, please visit the below URL:
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html