A large metal sheet carries an electric current along its surface with $ \lambda$ being the current per unit length. The value of the magnetic field near the surface of the sheet is

Question

$\begin {array} {1 1} (a)\;\mu_0 \lambda & \quad (b)\;\large\frac{\mu_0 \lambda}{2} \\ (c)\;\large\frac{\mu_0 \lambda}{2\pi} & \quad (d)\;\large\frac{\mu_0 \lambda}{\pi} \end {array}$