The correct option is A 2 units
The perpendicular bisector bisects the line AB at (0, 0). The given point A (-2, 0) lies on the negative side of the origin so point B lies on the positive side of the origin with coordinates, (2, 0).
Hence, the distance from the y-axis on either side of the origin should be same, i.e., 2 units.
Distance can never be negative. So it will be positive 2 units.