This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition and health, Subject name: Social & Preventive Medicine
[{'content': 'On exposure to sunlight which vitamin is lost - \nSelect and explain. \nA. Vitamin A, B. Vitamin B1, C. Vitamin B6, D. Vitamin C', 'role': 'user'}, {'content': "Answer: D \nExplanation: Vitamin C is the most sensitive of all vitamins to heat. (REF. PARK'S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICAL 21ST EDITION. PAGE NO - 621)", 'role': 'assistant'}]