Answer the following question given this paragraph: 

Ultrasound is sound that has a wave frequency higher than the human ear can detect. It includes all sounds with wave frequencies higher than 20,000 waves per second, or 20,000 hertz (Hz).


Q: What do you call sound that has a wave frequency higher than the human ear can detect?

 Choices:

- dynamic sound

- supersonic sound

- hypersonic sound

- ultrasound

A:
ultrasound
