Files uploaded to a user's private library in Salesforce Files Home are strictly private and visible only to the user who uploaded them. Even users with elevated permissions, such as those with "View All Data" access, or users higher in the Role Hierarchy, cannot view these files. This ensures the utmost privacy for files stored in a private library.
* Option A: Role Hierarchy does not affect access to files stored in a private library.
* Option B: "View All Data" does not grant access to files in private libraries.
* Option C (Correct): Only the user who uploaded the file can view it in their private library.
References:
* Files Home Overview
* File Privacy and Sharing