This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Which of the following is the poorest source of vitamin "C"? \nSelect and explain. \nA. Milk, B. Cabbage, C. Guava, D. Radish', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]