A point charge q is rotated along a circle in the electric field generated by another point charge Q . The work done by the electric field on the rotating charge in one complete revolution is

Question

$(a)\;zero\qquad(b)\;positive\qquad(c)\;negative\qquad(d)\;zero\;if\;the\;charge\;Q\;is\;at\;the\;centre\;and\;non-zero\;otherwise$