Two charges, each equal to q, are kept at $x = -a$ and $x= a$ on the x-axis. A particle of mass m and charge $q_{_0} = \frac{q}{2}$ is placed at the origin. If charge $q_{_0}$ is given a small displacement ( y a) along the y-axis, the net force acting on the particle i proportional to :

Question

( A ) $-y$
( B ) $-\frac{1}{y}$
( C ) $\frac{1}{y}$
( D ) $y$