The figure below depict two situations in which two infinitely long static line charges of constant positive line charge density `lambda` are kept parallel to each other. In their resulting electric field, point charges q and –q are kept in equilibrium between them. The point charges are confined to move in the x direction only. If they are given a small displacement about their positions, then the correct statement(s) is(are) :

Options

A. Both charges execute harmonic motion.
B. Both charge will continue moving in the direction of their displacement.
C. Charge +q execute simple haramonic motion while charge -q continues moving in the direction of its displacement.
D. Charge -q executes simple haramonic motion while charge +q continues moving in the direction of its displacement.

Answer

C