A company is hosting its website on a cluster of web servers behind a public-facing load balancer. The web application has interfaces with an AWS RDS database. The management has specified that the database needs to be available in case of a hardware failure on the primary database. The secondary needs to be made available in the least amount of time. Which of the following would you opt for?

Answer options:

A.Made a snapshot of the database
B.Enabled Multi-AZ failover
C.Increased the database instance size
D.Created a read replica

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). Thus you can resume database operations as soon as the failover is complete. 
Options A and D are incorrect since even though they can be used to recover a database, it would just take more time than just enabling Multi-AZ.
Option C is incorrect since this will not help the cause.
For more information on Multi-AZ, please visit the URL-
https://aws.amazon.com/rds/details/multi-az/