What kind of wave is created if a tree falls in a forest?

1. polarized wave

2. transverse wave

3. none of these

4. sound wave

5. electromagnetic wave

It is said that if a tree falls in a forest, and there is nobody there to hear it, it still creates a sound wave. (4)

It is also said that if a man speaks in the forest, and there is no woman there to hear him, he is still wrong nonetheless.