A Group of Organizations Follows the Same Access Standards and Practices

A group of organizations follows the same access standards and practices. One manages the verification and due diligence processes for the others. For a user to access a resource from one of the organizations, a check is made to see if that user has been certified. Which Federated Identity Management (FIM) process is this an example of?

A) One-time authentication
B) Web based access management
C) Cross-certification model
D) Bridge model