Lights, visibility, and being seen
Signals announce intention before movement
Signal early enough for others to understand your intention — but signalling does not give you the right of way.
What to watch for
The question mentions indicators, emergency lights, lane changes, turns, or stopping.
The rule
The rule explains exactly how to answer any question of this type — and why the obvious wrong answer fails.
See the rule →Common trap
Don't treat a signal as permission to move — you still need to check it is safe.