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': 'Selection bias can be eliminated by: \nSelect and explain. \nA. Randomization., B. Single blinding., C. Double blinding., D. Matching.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]