Answer:
Water is a solvent, and CO2 gas and the powdered drink mix are both solutes.
Explanation:
In order to successfully answer this question, we need to remember that solutions consist of solutes and solvents.
Solutes are components of solutions that are dissolved (typically ionic salts if we have a polar solvent), while solvents are fluids (usually liquids) that provide a medium for the solutes to dissolve (water is the most common polar solvent for ionic salts, for example).
As a general rule, solvent is used in great excess, that is, it makes the greatest percentage in terms of mass of a particular solution.
Applying the theory above for this problem, notice that the greatest percentage of this solution belongs to water, besides, water is a common solvent in general. Thus, it is our solvent.
Also, solution would only have one solvent and one or several solutes. This leaves the two other components, carbon dioxide and powdered drink mix, as our solutes, as they have a lower percentage than our solvent.