Two parallel wires carry currents $20A$ and $40A$ in the opposite directions. Another wire carrying a current $30A$ parallel to $40A$ is placed mid-way between the two wires. The force on it will be

Question

$\begin {array} {1 1} (a)\;Towards\: 20A & \quad (b)\;Towards\: 40A \\ (c)\;Perpendicular \: to\: both\: 20A\: and\: 40A & \quad (d)\;Zero \end {array}$