I heard some cackling in the background ( I hope they were n't watching it on the monitor ) . I tried to do it as quickly as possible . A couple of times , someone tried to open the door .
What is a likely source of the cackling that was heard by the speaker ?
Pick the best answer from the following options:
A. There is a wild animal inside making this noise
B. Someone is choking , making a cackling sound
C. None of the above choices .
D. Someone is watching them and laughing


D