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
Which of the following antiretroviral drugs is a non-nucleoside reverse transcriptase inhibitor - 
Select and explain. 
A. Zidovudine, B. Efavirenz, C. Saquinavir, D. Stavudine
B: Efavirenz
Answer: B: Efavirenz 
Explanation: None