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: Medicine
[{'content': "In PCR: \nSelect and explain. \nA. Thermostable enzyme is needed, B. 211 copies formed after 'n' numbers of multiple, C. Non specific, D. Thermolabile enzyme", 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Thermostable enzyme is needed', 'role': 'assistant'}]