A student placed 3.0 grams of Mg into some HCl in two different experiments. In each case, it reacted according to the following equation: Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g). In the first experiment, it took 32 minutes for all of the Mg to react. In the second experiment, it took 54 minutes for all of the Mg to react. Which of the following could account for the change in reaction rate of the second experiment? A. a catalyst was added B. the Mg was powdered into H2 C. the H2 was decreased D. the temperature was decreased