ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received✓Correct answer
ALE radios monitor an internet site for the frequency they are being paged on
ALE radios send a constant tone code to establish a frequency for future use
ALE radios activate when they hear their signal echoed by back scatter
Explanation
An ALE controller sits scanning its list of channels, and when it hears a call addressed to its own station's address it stops, sounds back and brings up the link on whichever channel is propagating. There is no internet lookup, no constantly transmitted tone, and no dependence on hearing an echo of its own signal.