The correct answer is b) water.
Soda is primarily a solution of carbonated water, which means that water is the main component and acts as the solvent in the mixture. The carbon dioxide gas is dissolved in the water, giving soda its fizz and slightly acidic taste. Sugar is present mainly as a solute, which is dissolved in the water to provide sweetness. So, in this case, water is the solvent that helps to dissolve both the sugar and the carbon dioxide.