Answer : Option 4) \(CO_{2}_{(aq)}\)
Explanation : \(CO_{2}_{(aq)}\) is the only sample of matter which can be classified as a solution. As the solution can be defined as a liquid mixture which contains a minor component (the solute) that is uniformly distributed within the major component (the solvent).
In this case, the solute is \(CO_{2}\) which is dissolved in water which acts as an solvent. Also, it has a subscript which is aq. which means aqueous, is often given to the solution in which the solvent is water.
Therefore, \(CO_{2}_{(aq)}\) is the correct answer.
