As the diameter of objective lens of a telescope increases, the resolution of telescope

Correct answer: (c) Increases

Explanation

A telescope's resolving power is limited by diffraction, with resolving angle θ ∝ λ/D, where D is the objective lens diameter.

A larger diameter (aperture) gives a smaller θ, gathers more light and resolves finer detail, so resolution increases with diameter.

Resolution depends on aperture, not focal length, ruling out the other options.