75. A newborn is diagnosed to have severe metabolic acidosis, ketosis, and hyperammonemia. Plasma amino acid analysis shows markedly elevated branched-chain amino acids. Which of the following statements is correct? I. The primary defect is in the degradation of leucine, isoleucine, and valine. II. The enzyme deficiency affects a complex that requires biotin as a cofactor. III. Restriction of aromatic amino acids in the diet is the key step of treatment. (A) I and II (B) II and III (C) I and III (D) I only (E) All of them are correct.