Answer:
Option B. The planet is a very way from the center or the Sun.
Step-by-step explanation:
If the surface temperature of the newly formed planet is - 20 K that means the distance of the planet from the sun in greater.
If we look at the temperature trends of the planets in our solar system, the planets closer to the sun like Mercury, Venus have very high surface temperature but as we move move away from the the center of the solar system, i.e., Sun, the temperature goes on decreasing.