A company uses AWS Organizations.

AWS CloudHSM is aVPC-scopedservice: the HSMs (and the CloudHSM cluster) live inside a VPC in the central account, and clients connect over the network to perform cryptographic operations. When another account needs to use a centrally managed CloudHSM cluster, the right approach is toshare the CloudHSM clusterwith that account and allow network connectivity from the consuming account’s clients. AWS provides cross-account resource sharing throughAWS Resource Access Manager (AWS RAM)for supported resources, including CloudHSM clusters. Sharing thecluster/HSM identifieris what grants the consuming account visibility/ability to create client configurations against that shared cluster.

After sharing, the consuming account’s EC2 instances (CloudHSM clients) still must be able to reach the HSM ENIs over the network, so the CloudHSM security group in the central account must allow inbound connections from the client sources (typically by security group referencing via VPC connectivity, or by allowing the relevant IP range/ports as appropriate).

Option A is incorrect because sharing asubnet IDdoes not share the CloudHSM resource itself. Options B and C misuse IAM/STS: CloudHSM cryptographic operations are not granted via assuming an IAM role into the central account; access is based oncluster sharing + network connectivity + CloudHSM user authenticationat the HSM level.