Two thin long parallel wires separated by a distance d carry a current i amp in the same direction. They will

• A

  repel each other with a force  ${\mathrm{\mu }}_0{\mathrm{i}}^2/\left(2{\mathrm{\pi d}}^2\right)$

• B

  attract each other with a force of ${\mathrm{\mu }}_0{\mathrm{i}}^2/\left(2{\mathrm{\pi d}}^2\right)$

• C

  repel each other with a force of ${\mathrm{\mu }}_0{\mathrm{i}}^2/\left(2{\mathrm{\pi d}}^2\right)$

• D

  attract each other with a force ${\mathrm{\mu }}_0{\mathrm{i}}^2/\left(2\mathrm{\pi d}\right)$