This graph shows how the concentration of the product of a reaction changed during a chemical reaction. Which sentence best describes how the concentration of the product changed? 1.0 0.8 0.6 Concentration of junpoid 0.4 0.2 0 20 80 100 40 60 Time A. It increased immediately as the reaction progressed. B. It decreased gradually as the reaction progressed. C. It decreased immediately as the reaction progressed. D. It increased gradually as the reaction progressed.​