Let the tangents drawn to the circle, $x^2+y^2=16$ from the point $P(0, h)$ meet the x-axis at points A and B. If the area of $DAPB$ is minimum, then h is equal to :

Question

$\begin{array}{1 1} 4 \sqrt 3 \\ 3 \sqrt 3 \\ 3 \sqrt 2\\ 4 \sqrt 2 \end{array} $