This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cold Chain in India, Subject name: Social & Preventive Medicine
[{'content': 'Dial thermometer works on the principle of:- \nSelect and explain. \nA. Thermocouple, B. Convection, C. Electromagnetic waves, D. Conduction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Dial Thermometer:- Principle: Thermocouple Measure ILR temperature twice a day Alcohol stamp thermometer is more sensitive but dial thermometer is more easy to use.', 'role': 'assistant'}]