Two long, thin, parallel conductors carrying equal currents in the same direction are fixed parallel to the x-axis, one passing through y = a and the other through y = -a. The resultant magnetic field due to the two conductors at any point is B. Which of the following are correct?
(a) B = 0 for all points on the x-axis.
(b) At all points on the y-axis, excluding the origin, B has only a z-component.
(c) At all points on the z-axis, excluding the origin, B has only a y-component.
(d) B cannot have an x-component.
