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: Microbiology
Which of the following is most sensitive for diagnosis of HIV? 
Select and explain. 
A. PCR, B. bDNA assay, C. NASBA, D. P24 detection
A: PCR
Answer: A: PCR 
Explanation: Ans. a. PCR