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': 'World Health Day is celebrated on: \nSelect and explain. \nA. 1st December, B. 31st may, C. 7th april, D. 8th may', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 7th April', 'role': 'assistant'}]