A coin is placed on a horizontal platform which undergoes vertical simple harmonic motion of angular frequency $\omega$. The amplitude of oscillation is gradually increased. The coin will leave contact with the platform for the first time:

Question

( A ) for an amplitude of $g/\omega^2$
( B ) at the highest position of the platform
( C ) at the mean position of the platform
( D ) for an amplitude of $g^2/\omega^2$