You have a Visual Studio Team Foundation Server 2010 environment. All contractors in your organization are members of a Team Foundation Server security group named Contractors that has been granted only the Read version control permissions. Lead developers have been granted all version control permissions. You need to implement a workflow that requires lead developers to review the source code changes made by contractors before they are committed to version control. Which two actions should you perform? (Each correct answer presents part of the solution.
Choose two.)

A.
Grant the Check In version control permissions to the Contractors security group.

B.
Grant the Check Out version control permissions to the Contractors security group.

C.
Instruct contractors to create a shelveset that includes the pending changes. Require that a lead developer check in the source code changes on behalf of the contractors.

D.
Instruct contractors to check in the source code changes. Require that a lead developer review the changeset and roll back the changeset if necessary.