Let $P(x, y, z)$ be a point in the first octant,whose projection in the $xy$-plane is the point $Q$. Let $OP = \gamma$; the angle between $OQ$ and the positive $x$-axis be $\theta$; and the angle between $OP$ and the positive $z$-axis be $\phi$,where $O$ is the origin. Then the distance of $P$ from the $x$-axis is:

• A
  $\gamma \sqrt{1-\sin^2 \phi \cos^2 \theta}$
• B
  $\gamma \sqrt{1+\cos^2 \theta \sin^2 \phi}$
• C
  $\gamma \sqrt{1-\sin^2 \theta \sin^2 \phi}$
• D
  $\gamma \sqrt{1+\cos^2 \phi \sin^2 \theta}$