Two point charges `+q` and `-q` are held fixed at `(-d,o)` and `(d,0)` respectively of a x-y coordinate system. Then
A. The electric field E at all points on the x-axis has the same direction
B. No work has to be done in bringing a test charge from `oo` to the origin
C. Electric field at all point on y-axis is parallel to x-axis
D. The dipole moment is 2 qd along the -ve x-axis