UPSC NDA I 2023 General Ability Solved Paper

A rectangle ABCD is kept in front of a concave mirror of focal length f with its corners A and B being, respectively, at distances 2f and 3f from the mirror with AB along the principal axis as shown in the figure. It forms an image A′B′C′D′ in front of the mirror. What is the ratio of B′C′ to A′D′ ?