A parent is concerned about their child's phone connecting to unknown Bluetooth devices. On iOS, what setting can prevent an iPhone from being discoverable to all nearby Bluetooth devices while still allowing paired devices to connect?

• A.A. Disabling Bluetooth entirely in Settings prevents all connections including paired devices
• B.B. iPhones automatically become non-discoverable (not broadcasting their device name to unpaired devices) as soon as the Bluetooth settings pane is closed; paired devices can still reconnect without the device being in discovery mode
• C.C. Setting the phone to 'Stealth Mode' in Bluetooth settings hides it from all nearby scanners including paired devices
• D.D. The parent must enable Guided Access to prevent Bluetooth discovery by third-party apps