Answer: Cowell
Explanation:
The first one who experimented with piano strings and clusters is Henry Cowell.
He was the first one who asked the pianist to manipulate string and then when he discovered the sound.
Before that new sound, he discovered also <u>tone clusters</u>. Tone clusters were achieved by hitting the piano keys with elbows or fists.
D. ABCD is the correct representation of the Rondo Form. I hope this helped you. Please give brainliest. :)
He refers to the jazz age using instruments.