Three points charges +q,-2q and +q are placed at points (x=0,y=a,z=0),(x=0,y=0,z=0)and (x=a,y=0,z=0) respectively.The magnitude and direction of the electric dipole moment vector of this charge assembly are .

Options

A. `sqrt 2`qa along + x direction
B. `sqrt 2`qa along + y direction
C. `sqrt 2`qa along the line joining points (x=0,y=0,z=0)and()x=a,y=a,z=0)
D. qa along the line joining points(x=0,y=0,z=0)and (x=a,y=a,z=0)