Two parallel wires in free space are 10 cm apart and carry currents of 10 A each in the same direction. The force each wire exerts on the other per meter of length is
a) 2 * 10-4 N, repulsive
b) 2 * 10-7 N, attractive
c) 2 * 10-7 N, repulsive
d) 2 * 10-4 N, attractive