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 equilibrium 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