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': 'Not a feature of hard water is \nSelect and explain. \nA. Increased fuel consumption, B. Erosion of lead pipe, C. Scaling of boiler, D. Decreased soap consumption', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]