When blue food coloring is dissolved in water, the result is a homogeneous mixture called a solution. So the correct answer is A.
To explain further, a homogeneous mixture is one where the components are evenly distributed and not easily distinguishable. In the case of food coloring, when it is added to water, it disperses evenly throughout the liquid, creating a uniform color. This even distribution means that no separate layers or particles can be seen, which is characteristic of a solution. In contrast, a heterogeneous mixture would have visibly different components that you could separate, such as oil and water, where the oil would float on top. Therefore, the accurate classification of this scenario is a homogeneous mixture known as a solution.