From which source environment can content be copied to Stage using Content Sets in Cloud...

Cloud Manager’s Content Copy feature allows administrators to copy content from Production to non-production environments such as Stage or Development. This is intended to provide accurate and representative content for testing, QA, or UAT purposes. Content cannot be copied from Development or Integration to Stage, as Adobe enforces strict controls to prevent non-production content from contaminating Production or Stage environments. Option C is correct because Production is the only valid source environment for copying content to Stage. Adobe emphasizes that copying content from Production ensures consistency and valid test data while maintaining governance and security in AEMaaCS.