Venus has a dense atmosphere that traps heat, raising the average surface temperature
Option C.
Explanation:
Venus is the planet in our solar system which is second most closest planet to the Sun. And it's well known for its surface temperature which is often exceeding a temperature of 480°C. Although the planet is lying far enough from sun, much farther than mercury, but the secret behind its highest surface temperature lies in its atmosphere.
Venus has an atmosphere which is 4 times denser than that of earth. And it's atmosphere is composed of 95.6% carbon dioxide. This is well known as a greenhouse gas. The atmosphere in venus is so thick that the surface of venus is never visible from earth. The dense atmosphere also consists of clouds of sulphuric acid and nitric acids.