Answer: The correct answer is phase.
Step-by-step explanation:
Phase is defined as region of space in which properties of matter are distributed uniformly with distinct boundary due which they are mechanically separable.
In a chemical reaction , when to substances reacts together they are called reactants and new substance formed from the reactions is called products.
Solvent is defined those substance which capable of dissolving other substance in them.
Hence, the correct answer is phase.