the whistle material to shake. the air inside the whistle to vibrate. the air to be absorbed by the whistle. the air in the whistle to heat up and expand.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A whistle produces a sound because blowing air in the whistle causes
Possibilities:
- the whistle material to shake.
- the air inside the whistle to vibrate.
- the air to be absorbed by the whistle.
- the air in the whistle to heat up and expand.

the air inside the whistle to vibrate.