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': "EIKJMAN'S test used in \nSelect and explain. \nA. As coliform test, B. To determine chlorine demond, C. Air quality test, D. Humidity test", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]