8. Three parallel straight wires lie in the same plane and carry equal currents I, as shown below. The current in the outer wires is directed to the right, and that in the center wire is directed to the left. Each of the outer wires is a distance R from the central wire. The direction of the magnetic force on the top wire a. is up out of the plane of the wires (out of the page). b. is down into the plane of the wires (into the page). c. is in the plane of the wires, directed upwards (toward the top of the page). d. is in the plane of the wires, directed downwards (toward the bottom of the page). e. cannot be defined, because there is no magnetic force on the top wire