To satisfy the requirements, which one of these services can the SysOps administrator enable at-rest encryption on?

An existing, deployed solution uses Amazon EC2 instances with Amazon EBS General Purpose SSD volumes, an Amazon RDS PostgreSQL database, an Amazon EFS file system, and static objects stored in an Amazon S3 bucket. The Security team now mandates that at-rest encryption be turned on immediately for all aspects of the application, without creating new resources and without any downtime.

To satisfy the requirements, which one of these services can the SysOps administrator enable at-rest encryption on?
A . EBS General Purpose SSD volumes
B . RDS PostgreSQL database
C . Amazon EFS file systems
D . S3 objects within a bucket

Answer: B