This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
a 40 yr old man underwent renal transplantation two months after transplantation he developed fever and features suggestive of bilateral diffuse interstitial pnuemonitis. what is causative agent ? 
Select and explain. 
A. HSV, B. CMV, C. EBV, D. VZV
B: CMV
Answer: B: CMV 
Explanation: PERSONS WITH HIGH RISK OF CMV INFECTION : organ transplantation with malignant tumors who are recieving chemotherapy with hiv/aids viral excreation is icreased and prolonged diffuse interstitial pneumonia is common complication ref : ananthanaryana 9th ed