This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
Which of the following is associated with highest risk of HIV transmission? 
Select and explain. 
A. Blood transfusion, B. Disposable needle prick, C. Sexual transmission, D. Mother to baby
A: Blood transfusion
Answer: A: Blood transfusion 
Explanation: Ans. a (Blood transfusion). (Ref. Park, PSM, 18th ed., 98, 338)# Among all sources of HIV heterosexual promiscuity are major route and 85% HIV infections occur due to unprotected and multiple sexual contacts with the risk of 0.3 to 3%.# The highest risk of HIV transmission is with blood transfusion (90-95%).