A transparent and homogeneous sphere of glass of radius $$r$$ is immersed in water, refractive indices of glass and water being $$\frac{3}{2}$$ and $$\frac{4}{3}$$. The image of a point object $$O$$, located at distance $$d$$ on its axis in front of the sphere, is formed at point $$I$$ at the same distance $$d$$ from the sphere on the opposite side as shown. The distance $$d$$ is equal to

A

$$2r$$

B

$$3r$$

C

$$6r$$

D

$$8r$$