What should a developer do to ensure the data is encrypted on disk without impacting performance?

A company is building a compute-intensive application that will run on a fleet of Amazon EC2 instances. The application uses attached Amazon EBS disks for storing data. The application will process sensitive information and all the data must be encrypted.

What should a developer do to ensure the data is encrypted on disk without impacting performance?
A . Configure the Amazon EC2 instance fleet to use encrypted EBS volumes for storing data
B . Add logic to write all data to an encrypted Amazon S3 bucket
C . Add a custom encryption algorithm to the application that will encrypt and decrypt all data
D . Create a new Amazon Machine Image (AMI) with an encrypted root volume and store the data to ephemeral disks.

Answer: A