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: Pathology
Most common cause for complication of blood transfusion is? 
Select and explain. 
A. Human error, B. Anaphylaxis, C. GVHD, D. Presensitisation
A: Human error
Answer: A: Human error 
Explanation: Ans. is 'a' i.e., Human error The most common cause resulting in complications from blood transfusion is human error Acute hemolytic reaction resulting from ABO incompatibility is the most serious complication of blood transfusion.