Their masses increased. They lost most of their radioactive isotopes. Their structures differentiated into distinct layers. They started to revolve around the Sun.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which change resulted from the heating of the planets as they formed?
Possibilities:
- Their masses increased.
- They lost most of their radioactive isotopes.
- Their structures differentiated into distinct layers.
- They started to revolve around the Sun.

Their structures differentiated into distinct layers.