The correct answer is B. OAuth app policy.
An OAuth app policy is a type of policy that allows you to control the permissions and access of third-party apps that use OAuth to connect to your cloud apps, such as Microsoft 365, Google Workspace, and Salesforce. You can create an OAuth app policy based on various criteria, such as the app name, the permission level, the number of users who authorized the app, and the group memberships of those users. You can also set an alert action for the policy, which will notify you when an app meets the conditions you specified. For example, you can create an OAuth app policy that will alert you when there are apps that require a high permission level and are authorized by more than 20 users1.