What is the expression for the gravitational force according to Coulomb's law? I- F = k(q1q2)/r^2 II- F = k(q1q2)/r III- F = kq1q2 IV- F = kq1q2/r...

What is the expression for the gravitational force according to Coulomb's law?

I- F = k(q1q2)/r^2
II- F = k(q1q2)/r
III- F = kq1q2
IV- F = kq1q2/r^2
a) I and III are correct.
b) II and IV are correct.
c) I and IV are correct.
d) II and III are correct.