4. Chef Mariel left a plate of chopped apple, a plate of lettuce and a cup of pineapple in the table to answer a phone call. When she comes back, she found out that the fruit and vegetable discoloured into brown. What phenomena explain this? A. The browning of the fruit and the vegetable is a spontaneous process. B. The browning of the fruit and the vegetable is due to the food color added into it? C. The browning of fruit and vegetable is unexplainable. D. The browning of fruit and vegetable is due to the tarnishing of the knife used in chopping.​