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: Surgery
[{'content': "ABO antigens are not seen in aEUR' \nSelect and explain. \nA. C.S.F., B. Saliva, C. Semen, D. Sweat", 'role': 'user'}, {'content': 'Answer: A \nExplanation: C.S.F. ABO antigens are found in Sal PancreasQ Kidney Liver Semen Sweat Gastric juice Amniotic fluid Lung', 'role': 'assistant'}]