Correct Answer - A
Over `Q_1` potential is `+alpha`. Hence `Q_1` is positive.
`V_A=0` and A point is nearer to `Q_2`. Therefore `Q_2` should be negative and `|Q_1|gt|Q_2|`.
At A and B, potential is zero, not the force.
Equilibrium at C will depend on the nature of charge with is kept at C.