AWS Certified SysOps Administrator Associate SOA-C02 – Question41

A company's SysOps administrator has created an Amazon EC2 instance with custom software that will be used as a template for all new EC2 instances across multiple AWS accounts. The Amazon Elastic Block Store (Amazon EBS) volumes that are attached to the EC2 instance are encrypted with AWS managed keys.
The SysOps administrator creates an Amazon Machine Image (AMI) of the custom EC2 instance and plans to share the AMI with the company's other AWS accounts. The company requires that all AMIs are encrypted with AWS Key Management Service (AWS KMS) keys and that only authorized AWS accounts can access the shared AMIs.
Which solution will securely share the AMI with the other AWS accounts?

A.
In the account where the AMI was created, create a customer master key (CMK). Modify the key policy to provide kms:DescribeKey, kms:ReEncrypt*, kms:CreateGrant, and kms:Decrypt permissions to the AWS accounts that the AMI will be shared with. Modify the AMI permissions to specify the AWS account numbers that the AMI will be shared with.
B. In the account where the AMI was created, create a customer master key (CMK). Modify the key policy to provide kms:DescribeKey, kms:ReEncrypt*, kms:CreateGrant, and kms:Decrypt permissions to the AWS accounts that the AMI will be shared with. Create a copy of the AMI, and specify the CMK. Modify the permissions on the copied AMI to specify the AWS account numbers that the AMI will be shared with.
C. In the account where the AMI was created, create a customer master key (CMK). Modify the key policy to provide kms:DescribeKey, kms:ReEncrypt*, kms:CreateGrant, and kms:Decrypt permissions to the AWS accounts that the AMI will be shared with. Create a copy of the AMI, and specify the CMK. Modify the permissions on the copied AMI to make it public.
D. In the account where the AMI was created, modify the key policy of the AWS managed key to provide kms:DescribeKey, kms:ReEncrypt*, kms:CreateGrant, and kms:Decrypt permissions to the AWS accounts that the AMI will be shared with. Modify the AMI permissions to specify the AWS account numbers that the AMI will be shared with.

Correct Answer: C