Two long, straight, parallel wires are oriented perpendicular to the xy-plane and carry equal currents I in opposite directions. Wire 1 passes through the origin (x, y) = (0, 0) with current directed out of the page (+z-direction). Wire 2 passes through (x, y) = (d, 0) with current directed into the page (-z-direction). The +y-direction is directed toward the top of the page. Which of the following graphs best represents the y-component of the net magnetic field, B_y, along the x-axis in the region 0 < x < d?