Your company has recently deployed a web application in the AWS Cloud. As a Solutions Architect, you are required to ensure that security is maintained in accordance with best practices. Considering the AWS shared responsibility model, which of the following is AWS's responsibility?
Applying security groups to your EC2 instances.
Maintaining the underlying hypervisor security for EC2 instances.
Installing security patches within your RDS instances.
Ensuring encryption of EBS volumes attached to EC2 instances.