Which one of the following statements concerning glucose metabolism is correct? (A) The conversion of Glucose to lactate occurs only in the R.B.C (B) Glucose enters most cells by a mechanism in which Na+ and glucose are co-transported (C) Pyruvate kinase catalyses an irreversible reaction (D) An elevated level of insulin leads to a decreased level of fructose 2, 6-bisphosphate in hepatocyte