This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins and Minerals, Subject name: Biochemistry
[{'content': 'Which of the following tocopherol is the most active form of vitamin E? \nSelect and explain. \nA. Alpha, B. Beta, C. Gamma, D. Delta', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Vitamin E family contains tocopherols and tocotrienols. There are 4 vitamers a, b, g and d in each group. a-tocopherol is the most active form. Look at the isoprene side chain of tocopherol. All fat-soluble vitamins contain isoprene units. Structure of alpha tocopherol', 'role': 'assistant'}]