Of the choices given, which one identifies the Android security model's fundamental app isolation mechanism?

• A.Apps are isolated by cryptographic containers (each package gets a volume of its own), and the framework unwraps that volume at launch, leaving the filesystem with no notion of ownership
• B.Each app is assigned a unique Linux user ID (UID) and runs in its own process, preventing apps from accessing each other's files or memory without explicit permission
• C.Each app runs inside its own browser tab (the platform hosts them in a shared WebView process), and the tab boundary is what keeps one app out of another's stored data
• D.Android enforces isolation with a whitelist of approved packages (the list is refreshed by Play Protect), and an app absent from that list is denied access to the framework interfaces