Answer: Picture (d) is the correct answer.
Step-by-step explanation:
When liquid nitrogen is at -320 degrees then as the temperature is very low, therefore, molecules of nitrogen will be much closer to each other.
Whereas when liquid nitrogen is boiled then we are increasing the temperature. As a result, force of attraction between the molecules decreases and they will move far apart from each other.
It is known that below 63 K liquid nitrogen tends to freeze and thus it becomes solid. So, at -320 degrees liquid nitrogen will be in solid state.
In the given pictures, picture (d) represents the change caused by adding heat to liquid nitrogen.