What does "prevalence" mean? What axis represents prevalence?

Question

A:Prevalence means how common something is. It's on the X axis.
B:Prevalence means how useful something is. It's on the X axis.
C:Prevalence means how common something is. It's on the Y axis.
D:Prevalence means how useful something Is. It's on the Y axis.

Answer 1

C: Prevalence means how common something is. It's on the Y axis.

Answer 2

It wasn’t c

Answer 3

I apologize for the error. The correct answer is:

A: Prevalence means how common something is. It's on the X axis.