Two point charges q and -2 q are located at (a, 0,0) and (0,0,0) respectively. Assume that the potential V is vanishing at infinity. The correct statement about the V=0 surface (at finite distance) is:

Options

1. Aa plane perpendicular to x -axis and passing through (2 a, 0,0) .
2. Ba plane perpendicular to x -axis and passing through (2 a / 3,0,0) .
3. Ca sphere centered at (4 a / 3,0,0) and of radius 2 a / 3 .
4. Da cylinder whose axis passes through (4 a / 3,0,0) and of radius 2 a / 3 .