This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Techniques in molecular biology, Subject name: Biochemistry
[{'content': 'PCR is primarily a \nSelect and explain. \nA. DNA degradation technique, B. DNA amplification technique, C. DNA sequencing technique, D. All of these', 'role': 'user'}, {'content': 'Answer: B \nExplanation: PCR (Polymerase chain reaction) DNA amplification technique. Even a single copy of DNA can be amplified to billion-fold due to exponential amplification.', 'role': 'assistant'}]