13. Two large parallel conducting plates P and Q are connected to a battery of emf E, as shown above. A test charge is placed successively at points I, II, and III. If edge effects are negligible, the force on the charge when it is at point III is
(A) of equal magnitude and in the same direction as the force on the charge when it is at point I
(B) of equal magnitude and in the same direction as the force on the charge when it is at point II
(C) much greater in magnitude than the force on the charge when it is at point II, but in the same direction
(D) much less in magnitude than the force on the charge when it is at point II, but in the same direction