How can you secure data at rest on an EBS volume?

A.
Attach the volume to an instance using EC2’s SSL interface.

B.
Write the data randomly instead of sequentially.

C.
Encrypt the volume using the S3 server-side encryption service.

D.
Create an IAM policy that restricts read and write access to the volume.

E.
Use an encrypted file system on top of the EBS volume.

Explanation:
https://aws.amazon.com/blogs/aws/protect-your-data-with-new-ebs-encryption/