The CISO of your highly regulated organization has mandated that all AI applications running in...

In the Google Cloud resource hierarchy, Organization Policy is a powerful tool for governance, but its effectiveness depends on strict control over who can modify it. If a policy set at the folder level was "overwritten," it means a principal with the Organization Policy Administrator role (roles/orgpolicy.policyAdmin) at the project level (or folder level) changed the inheritance or defined a more permissive policy.1

According to Google Cloud Documentation (Organization Policy Service - IAM Roles):

"To manage organization policies, a principal must have the Organization Policy Administrator role. This role should be granted only at the Organization level to a limited set of trusted security or compliance administrators to prevent project owners from overriding security guardrails."

Why Option A is the best fix:

By removing the role from everyone except the central security team at the Organization level, you ensure that no one else has the technical permission to "Manage Policy" or click "Override" at any child node (folder or project).

B is insufficient because if a user has the role at the organization level, they can still apply overrides at the folder or project level.

C and D (Security Postures) are detective controls. While the secure_ai_extended template helps monitor drift, it does not prevent the occurrence. The question asks for a solution that "prevents a repeat occurrence," which requires a preventative IAM change.