Comprehensive and Detailed Explanation:

The Secure File-Sharing Application, provided and managed by the DoD, operates under the government’s authorization boundary, not the contractor’s. The CMMC Assessment Scope - Level 2 excludes assets owned and secured by the government from the OSC’s scope, as they fall outside the contractor’s control. While the contractor uses it to transfer CUI, their responsibility lies in securing their own systems (e.g., NGFW, SSD), not the DoD application. The SSP should document data flow to this application, but it is not assessed as part of the OSC’s scope. Option B applies to contractor-managed CUI assets, Option C to security tools, and Option D to risk-managed assets—all inapplicable here.