The figure shows a simple arrangement which works as an astronomical telescope. The arrangement consists of two convex lenses placed coaxially. The lens which faces a distant object is called the objective. It has a large aperture and a large focal length also. The second lens is closed to the observers eyes. It is called the eyepiece. It has a smaller aperture as compared to the objective. Its focal length is also small in comparison to objective. The objective forms a real image of a distant object. This image acts as the object for the eyepiece. The eye-piece may form its image at a large distance `(oo)` or at least distance of distinct vision (D = 25 cm). The magnifying power of the telescope is the ratio `(-beta)/(alpha)`. Maximum angular magnification is produced when the final image is at the least distance of distinct vision. The length is telescope is the distance between objective lens and eye-piece lens. When the telescope is adjusted to give maximum angular magnification for a distant object the length L of the telescope isA. `L = f_(0) + f_(e)`B. `L lt f_(0) + f_(e)`C. `L gt f_(0) + f_(e)`D. `L = f_(0) - f_(e)`