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: Social & Preventive Medicine
[{'content': "Cow's milk contains what % proteins – \nSelect and explain. \nA. 1.1, B. 3.2, C. 3.5, D. 4.1", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]