This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Bio-Chemistry), Subject name: Biochemistry
[{'content': 'Vitamin-Bl is named so because \nSelect and explain. \nA. First to be discovered in B complex vitamins, B. First to be classified in B complex vitamins, C. Most important vitamin for the body, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) First to be discovered in B complex vitamins > Thiamine was the first of the water-soluble vitamins to be described, leading to the discovery of more such trace compounds essential for survival and to the notion of vitamin.', 'role': 'assistant'}]