Three point charges of each of charge q are placed on three vertices of a square of side "l" meter . Find the magnitude of electric field at the centre of the square .

Question

$(a)\;\large\frac{kq}{l^2}\qquad(b)\;\large\frac{kq}{2l^2}\qquad(c)\;\large\frac{2kq}{l^2}\qquad(d)\;none$