<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 24-year-old male presents to the emergency room with a cough and shortness of breath for the past 3 weeks. You diagnose Pneumocystis jiroveci pneumonia PCP. An assay of the patients serum reveals the presence of viral protein p24. Which of the following viral genes codes for this protein?? A: gag, B: pol, C: env, D: tat, E: rev,  <response>: This is a question about HIV biology. The patient has PCP, which is an opportunistic infection that occurs in HIVAIDS patients when their CD4 count drops below 200 cellsmm3. The presence of p24 viral protein indicates active HIV infection. p24 is part of the viral core and is encoded by the gag gene. So the answer is A.A: gag 