Consider Two Charged Spheres,one with Charge +2 C and the Other

Multiple Choice

Consider two charged spheres,one with charge +2 C and the other with −2 C.A proton (a positively charged particle) is at the point halfway between the spheres.What is not zero?

A) the potential energy of the proton
B) the work to move the proton from infinity to that point
C) the force on the proton
D) all of the three above are zero