68. Which of the following statements about cholesterol biosynthesis is correct? ① NADPH is not required for cholesterol biosynthesis. ② HMG-CoA reductase is the major control points of the overall process. ③ The conversion of one molecule of mevalonate into one molecule of isopentenyl pyrophosphate consumes three molecules of ATP. ④ The conversion of one molecule of HMG-CoA into one molecule of mevalonate consumes two molecules of NADH. ⑤ The addition of geranyl pyrophosphate to isopentenyl pyrophosphate to form farnesyl pyrophosphate is a head-to-tail reaction. (A) ①②③ (B) ①③⑤ (C) ②③④ (D) ②③⑤ (E) ②④⑤