$$\begin{gathered} A long overhead transmission line is 5.0 m above the ground and carries a direct current 120 A. The magnetic indcution at a point directly below the line will be \\ \left(a\right) 2.4\times {10}^{-7}T perpendicular to wire \\ \left(b\right) 4.8\times {10}^{-6}T perpendicular to wire \\ \left(c\right) 2.4\times {10}^{-7}T along the wire \\ \left(d\right) 4.8\times {10}^{-6}T along the wire \end{gathered}$$