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: Dental
[{'content': 'The sampling method used in pathfinder survey is \nSelect and explain. \nA. Stratified cluster sampling, B. Simple random sampling, C. Snowball sampling, D. Two stage sampling', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]