The distance between object and the screen is D. Real images of an object are formed on the screen two positions of a lens separated by a distance $\mathrm{d}$. What will be the ratio between the sizes of two images?
(A) $\left(\mathrm{D}^{2} / \mathrm{d}^{2}\right)$
(B) $(\mathrm{D} / \mathrm{d})$
(C) $\sqrt{(\mathrm{D} / \mathrm{d})}$
(D) $\left[(\mathrm{D}-\mathrm{d})^{2} /(\mathrm{D}+\mathrm{d})^{2}\right]$