This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
PCR detects 
Select and explain. 
A. Antigen, B. Antibody, C. Nucleic acid, D. All of the above
C: Nucleic acid
Answer: C: Nucleic acid 
Explanation: Polymerase chain reaction (PCR) is a technique used in molecular biology to amplify a single copy or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a paicular DNA sequenceRef: DM Vasudevan, 7th edition, page no: 638