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': 'Soft water has hardness levels of \nSelect and explain. \nA. 50, B. 100, C. 150, D. 200', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 50", 'role': 'assistant'}]