Read the following context and choose the best option to answer the question.
Context: 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 .
Question: What is a likely source of the cackling that was heard by the speaker ?
Options: 
- There is a wild animal inside making this noise
 - Someone is choking , making a cackling sound
 - None of the above choices .
 - Someone is watching them and laughing


Someone is watching them and laughing