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
In early AIDS infection of ELISA is negative what should be done - 
Select and explain. 
A. p24 antibody, B. gp 120 antibody, C. gp 120 antigen, D. p 24 antigen
D: p 24 antigen
Answer: D: p 24 antigen 
Explanation: None