An object and a screen are separated by a distance $$D$$. A convex lens of focal length $$f$$ such that $$4f < D$$, is moved between the object and the screen to get two sharp images. If the two positions of the lens are separated by a distance $$L$$, then

A

$$L$$ is equal to $$\sqrt{D(D - 4f)}$$.

B

object distance in one position is numerically equal to image distance in the other position.

C

the ratio of sizes of the two images is $$\frac{(D - L)}{(D + L)}$$.

D

the ratio of sizes of the two images is $$\frac{(D - L)^2}{(D + L)^2}$$.