The correct option is A 1-c, 2-d, 3-b, 4-a
(1) Stars have their own light and are visible at night as twinkling bodies.
(2) Objects in the sky are together known as celestial bodies.
(3) Planets do not have their own light. They get light from the stars. Hence they do not twinkle.
(4) When the sky is pollution-free it becomes more clear and it is easy to view the heavenly bodies.