Which container has the heaviest total weight of water?

Answer: C — The third container

The correct choice indicates that the third container has the heaviest total weight of water. This conclusion is based on the fundamental principle of comparing volumes of water and their respective weights. In general, water weighs approximately 8.34 pounds per gallon. Therefore, if the third container has a greater volume of water than the others, it will naturally have the greatest total weight. If the first and second containers each hold less water or if they contain water that is less densely packed than in the third container, then their weights will naturally be lower. By considering the parameters of volume and density of water, the assertion that the third container weighs the most aligns with basic principles of fluid dynamics and weight measurement. Understanding the reasons for water's weight and how volume corresponds to weight can help clarify such questions in the future.