This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: Pediatrics
[{'content': 'Best method to diagnose HIV in infancy is: \nSelect and explain. \nA. Western blot, B. ELISA, C. PCR, D. All', 'role': 'user'}, {'content': 'Answer: C \nExplanation: WHO recommends HIV testing: <18 months HIV DNA or RNA PCR or HIV culture >18 months IgG antibody to HIV by ELISA and western blot test', 'role': 'assistant'}]