A cylindrical block of mass \( M \) and area of cross section \( A \) is floating in a liquid of density \( \rho \) and with its axis vertical. When depressed a little and released the block starts oscillating. The period of oscillation is _______.
\( \pi \sqrt{\frac{2M}{\rho A g}} \)
\( 2\pi \sqrt{\frac{M}{\rho A g}} \)
\( 2\pi \sqrt{\frac{\rho A}{M g}} \)
\( \pi \sqrt{\frac{\rho A}{M g}} \)
