A company uses AWS Organizations to manage multiple AWS accounts.

According to AWS Cloud Operations and Governance documentation, AWS Trusted Advisor provides automated checks for security group rules across all accounts, including identifying ports open to 0.0.0.0/0.

When viewed in organizational mode, Trusted Advisor integrates with AWS Organizations, allowing administrators to access organization-wide security findings from a central management account. This approach requires no custom code, additional infrastructure, or manual inspection, providing immediate visibility and the lowest operational overhead.

AWS CLI scripts (Option A) or Lambda automation (Option C) introduce additional maintenance, and Amazon Inspector (Option D) is focused on instance-level vulnerabilities, not network access rules.

Therefore, Option B is the AWS-recommended CloudOps best practice for centralized and low-effort open-port auditing.