$A$ current-carrying coil is placed with its axis perpendicular to the $N-S$ direction. Let the horizontal component of the earth's magnetic field be $H_0$ and the magnetic field inside the loop be $H$. If a magnet is suspended inside the loop,it makes an angle $\theta$ with $H$. Then $\theta =$

• A
  $\tan^{-1}\left(\frac{H_0}{H}\right)$
• B
  $\tan^{-1}\left(\frac{H}{H_0}\right)$
• C
  $\csc^{-1}\left(\frac{H}{H_0}\right)$
• D
  $\cot^{-1}\left(\frac{H_0}{H}\right)$