I think it is C. I hope I helped.
Thick lens will have shorter and consequently thin lens will have greater focal length. Because, For a thick lens, the optical path length of the light is more, than for a thin lens, thus, the bending of light will be more in case of a thicker lens. Consequently, it has a shorter focal length.
Answer:
Electrons are not little balls that can fall into the nucleus under electrostatic attraction
Explanation:
