John Cage was a musician, famous for his work with prepared pianos. A prepared piano is when objects or 'preparations' are placed in the piano string, or over the string to change the sound it makes.
The first prepared pianos can be traced back to John Cage, who was prolific in this playing mode as he experimented with several materials on the strings which included screws, nuts, rubber, bamboo, weather stripping, plastic, cloth, and a variety of household items.
I suggest listening to his musical piece titled 4'33'', which is one of his most famous works, and an excellent piece of music.
The correct answer is letter B
Happy holidays! :)