Answer: Option (a) is the correct answer.
Step-by-step explanation:
A solution is a substance that contains two or more than two compounds which are evenly mixed together.
In a solution, one substance is solute and the other is solvent. The solute is dissolved in the solvent.
For example, when NaCl is dissolved in water then it means NaCl is the solute and water is the solvent.
Therefore, we can conclude that solutions are formed by 2 or more compounds.