Frederick has a lawnmower that is fueled by gasoline. His science teacher told him that not all of the energy stored in the gasoline in the lawnmower is converted into the energy of motion that spins the lawnmower blade. Which of the following statements is the most accurate explanation of this situation? A. An isolated system always loses energy to its environment. B. The total amount of energy never changes in an open system. C. Energy can leave an open system and enter the surroundings. D. The law of conservation of energy is not obeyed by isolated systems.