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': 'Alma ata Con frernce was held in - \nSelect and explain. \nA. 1978, B. 1956, C. 1977, D. 1948', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 1978", 'role': 'assistant'}]