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': 'Dehydration in a child with diarrhoea, thirst present, tears absent is \nSelect and explain. \nA. Moderate, B. Mild, C. Severe, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]