80. Which of the following statements about citric acid cycle are correct? ① Pyruvate dehydrogenase links glycolysis to the citric acid cycle. ② The products of citric acid cycle are not used for the production of ATP in cells. ③ The product of glycolysis forms acetyl-CoA for entering citric acid cycle. ④ Its intermediates are not used by other metabolic reactions. ⑤ The citric acid cycle is also called as the Krebs cycle or the tricarboxylic cycle. (A) ①②③ (B) ①②④ (C) ①②⑤ (D) ①③④ (E) ①③⑤