Most common infection occurs in transplant recipients:: (A) Cytomegalo virus, (B) Epstein Barr virus, (C) Hepatitis virus, (D) Polyoma virus
Answer is A. Ref. Textbook of Microbiology and Immunology BY Parija. Page. 487
 
Most common infection is CMV.
Below is the table of the infections in transplant recipients (Very important from Harrisons)