Your company has just started using the AWS RDS service. They have an application making requests to a MySQL instance on this service. Due to the sudden surge of high requests, you need to ensure that the backup activities on the database do not interfere with the database`s normal operation. Which of the following would help in this requirement?

Answer options:

A.Ensure that the underlying instance type RDS instance is using General Purpose SSD storage. This type of storage will have minimal impact on such operations.
B.Ensure that the underlying instance type RDS instance is using Enhanced Networking. This type of setting will have minimal impact on such operations.
C.Ensure that the Multi-AZ feature has been enabled for the underlying RDS Instance.
D.Ensure that cross-region replication is enabled for the underlying RDS Instance.

Answer - C
Option C is correct because, in a Multi-AZ deployment, Amazon RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone. The primary DB instance is synchronously replicated across Availability Zones to a standby replica to provide data redundancy, eliminate I/O freezes, and minimize latency spikes during system backups. Running a DB instance with high availability can enhance availability during planned system maintenance and help protect your databases against DB instance failure and Availability Zone disruption.
Points to remember for Multi-AZ deployments:
No failover occurs for DB operations: long-running queries, deadlocks, or database corruption errors.
We know that during the backups, for instance, taking snapshots, there is usually an I/O consumption that takes place. To avoid this when using a multi-AZ enabled RDS database engine, create a backup on the standby instance. With automated backups, I/O activity is no longer suspended on your primary during your preferred backup window since backups are taken from the standby.
Options A and B are incorrect because, using General Purpose SSD Storage or using Enhanced networking, our backup activities will interfere with normal database operation.
Option D is incorrect, Cross-region replication is a time-consuming process. Depending on the amount of data in the databases, this process can take hours to complete.
References:
https://aws.amazon.com/rds/faqs/
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.XRgn.html