Which of these statements comparing electric and gravitational forces is correct?
(a) The direction of the electric force exerted by one point particle on another is always the same as the direction of the  gravitational force exerted by that particle on the other.
(b) The electric and gravitational forces exerted by two particles on each other are inversely proportional to the separation of the particles.

(c) The electric force exerted by one planet on another is typically stronger than the gravitational force exerted by that same planet on the other.

(d) None of the above