This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
HTLV extyra gene is - 
Select and explain. 
A. Gag, B. Pol, C. ENV, D. px
D: px
Answer: D: px 
Explanation: some retrovirus such as HTLV and HIV carry a fouh gene tex or tat after the env gene REF:ANANTHANARAYAN AND PANIKER'S TEXTBOOK OF MICROBIOLOGY 9TH EDITION PAGE NO:567