This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
[{'content': 'In the krebs cycle, CO2 is released from a step catalyzed by which of the following enzyme? \nSelect and explain. \nA. Isocitrate dehydrogenase, B. succinate dehydrogenase, C. Aconitase, D. Succinate thiokinase', 'role': 'user'}, {'content': "Answer: A \nExplanation: Reference: Harper's Illustrated Biochemistry 31st edition Pg 151", 'role': 'assistant'}]