In which sentence do you find subject-verb agreement?

A. Farley or Farley's brother is helping me with the project.
B. Neither the clarinets nor the trumpets plays the melody correctly.
C. Where is your keys to my car?
D. If you look carefully, you'll see tomatoes is on that aisle.

I think it would be A , because "Or" joins the subjects, because only one person is helping?