When you put food coloring into water, the water will turn the color of the food coloring. When you leave a cut apple out, it will change to a brown color. Which of the two indicates a chemical reaction and why?

Food coloring because it is chemically changing the water to a different color.
Apple because it is chemically reacting with oxygen to create the brown color.
Food coloring because it indicates that there is a temperature in the water.
Apple because by cutting it, you are rearranging the apple molecules which is indicated by the brown color.