This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection, Subject name: Medicine
Oppurtunistic infection are seen in: 
Select and explain. 
A. AIDS, B. Autoimmune diseases, C. Organ transplantation, D. All
D: All
Answer: D: All 
Explanation: Ansr d (All)There is no doubt that AIDS and organ transplantation cause opportunistic infectionNotes: Commonest parasitic infection seen in AIDS is strongyloides stercolaris.