If two gears have moment of inertias as $$I_1$$ and $$I_2$$ respectively and mesh with a speed ratio $$\frac{\omega_2}{\omega_1} = n,$$ then equivalent momentof inertia of both gears referred to first one is

A

$$n^2 I_1 + I_2$$

B

$$I_1 + nI_2$$

C

$$nI_1 + I_2$$

D

$$I_1 + n^2 I_2$$