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

A

at the highest position of the platform

B

at the mean position of the platform

C

for an amplitude of $$\dfrac{g}{\omega^2}$$

D

for an amplitude of $$\dfrac{g^2}{\omega^2}$$