Answer:
It becomes gas
Step-by-step explanation:
The answer that makes most sense is "it becomes gas". The nucleus of a comet is a solid ball of ice, dust, and rock. When it nears the sun, the ice on the surface of the nucleus begins to sublimate, which means it turns directly from a solid to a gas. The solid components of the nucleus remain solid (the dust and rock), but the ice changes state. This process causes the nucleus to become surrounded by a cloud of gas and dust, called the coma, which can be many times larger than the nucleus itself.