Correct Answer is: (d)
The conductors BC and EF will together produce a magnetic field at P which **** in the xz-plane and is equally inclined to the x- and z-axes. The conductors AB and CD will together produce a magnetic field at P directed along the z-axis and of the magnitude B0 (say).
The conductors DE and FA will produce a field at P with the same magnitude B0, and directed along the x-axis. Thus, the field at P will have equal components in the x- and z-directions, and no component in the y-direction. It must therefore point in the direction (1/√2)(Vector i + Vector k).
