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
HIV RNA by PCR can detect as low as 
Select and explain. 
A. 30 copies viral RNA/ml of blood, B. 40 copies viral RNA/ml of blood, C. 50 copies of viral RNA/ml of blood, D. 60 copies of viral RNA/ml of blood
B: 40 copies viral RNA/ml of blood
Answer: B: 40 copies viral RNA/ml of blood 
Explanation: Ans. is 'b' i.e., 40 copies viral RNA/ml of blood