A hemispherical glass body of radius $10 cm$ and refractive index $1.5$ is silvered on its curved surface. A small air bubble is $6 cm$ below the flat surface inside it along the axis. The position of the image of the air bubble made by the mirror is seen:

Question

$\begin{array}{1 1}(1) 14\; cm \;below \;flat \;surface \\ (2) 30\; cm \;below\; flat\; surface\\ (3) 20\; cm\; below\; flat\; surface\\4) 16\; cm\; below \;flat\; surface \end{array}$