Answer: The correct answer is Option a.
Step-by-step explanation:
A solute is defined as a substance which is present in low proportion in a solution. It is dissolved in the solvent to form a solution.
A solvent is defined as the substance which is present in higher proportion in a solution. It is the substance in which solute gets dissolved.
A catalyst is defined as the substance which increases the rate of the reaction.
A solution is defined as the mixture of solute and solvent.
From the above information, we get that the correct option is Option a.