4.下列何種中間產物不存在於克柏氏循環(Kerbs cycle)中? (A)乙醯輔酉每 A(acetyl CoA) (B)磷酸甘油酸(phosphoglycerate) (C)檸檬酸(Citrate) (D)琥珀酸(succinate) (E)蘋果酸(malate)