Ray Optics

An object is placed at an unknown distance from a convex objective lens of focal length 5 cm . The objective lens forms a real image which acts as an object for a convex eyepiece of focal length 6.25 cm . The distance between the objective and eyepiece is 20 cm . The microscope is adjusted so that the final image is formed at the least distance of distinct vision $(25 \mathrm{~cm})$. Which of the following is correct?

A. Object distance $=7.5 \mathrm{~cm}$; Total magnification $=10$

B. Object distance = 10 cm ; Total magnification = 20

C. Object distance $=5 \mathrm{~cm}$; Total magnification $=20$

D. Object distance = 2.5 cm ; Total magnification = 10