The correct answer is A. Allowing social media access while blocking file uploads requires two types of control: application/site recognition and content/action awareness. Application Control identifies and controls access to social media applications and services. Content Awareness can match data/content characteristics and help enforce restrictions on what is transferred, such as files or sensitive content. Option B is wrong because NAT changes addresses and ports; it does not control social media upload behavior. Option C is unrelated to the upload-control requirement: Identity Awareness can restrict access by user or group, and VPN secures remote/site connectivity, but they do not directly block uploads on social platforms. Option D is also not the best answer: HTTPS Inspection may be needed to see encrypted upload traffic, and Threat Emulation can inspect suspicious files, but the core policy combination is Application Control plus Content Awareness. Reference topics: Application Control, Content Awareness, Access Control Policy, application/site and content-based enforcement.