Which mode disables all forms of communication on mobile devices?

Flight mode disables all forms of communication on mobile devices. When activated, it turns off the device's wireless capabilities, including cellular connectivity, Wi-Fi, and Bluetooth. This is particularly useful during air travel, as airlines require devices to be in this mode to prevent interference with the aircraft's navigation and communication systems.

In contrast, power-saving mode primarily focuses on extending battery life by reducing background activity and limiting the use of certain features, but it does not cut off communication entirely. Silent mode silences notifications and incoming calls but keeps the device fully functional in terms of communication. Do not disturb mode allows calls and notifications but selectively silences them based on user settings, enabling some communication to still occur. Therefore, flight mode is the only choice that completely disables all wireless communication functions on a mobile device.