Four charges , all of the same magnitude , are placed at the four corners of a square . At the centre of the square , the potential is `V` and the field is `E`. By suitable choice of the signs of the four charges ,which of the following can be obtained?
(i) `V = 0 , E = 0`
(ii) `V = 0 , E != 0`
(iii) `V != 0 , E = 0`
(iv) `V != 0 , E != 0`
A. `V=0,E=0`
B. `V=0,E!=0`
C. `V!=0,E=0`
D. `V!=0,E!=0`
