Answer:
D. Alarm
Explanation:
Imagine a scenario where a couple of kids are playing around, running wild and all of a sudden they hear heavy foot studs, they are all quiet, all eyes fixed to the doorway trying to know who would come in.
The characters are alarmed because of a particular action that occured for their previous action, ('popping') to stop.
Imagine "Lord of the Flies" with an adult coming in when they were having their frenzied hunting game. The moment they killed Simon
