This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Transplantation, Subject name: Surgery
[{'content': 'Human immunodeficiency virus (HIV) has been isolated from many body fluids. Which of the following is a major source of transmission? \nSelect and explain. \nA. Tears, B. Sweat, C. Semen, D. Urine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: HIV has been isolated from blood, semen, vaginal secretions, saliva, tears, breast milk, CSF, amniotic fluid, and urine. It is an extremely fastidious virus that ordinarily is transmitted only after repeated admixture of body fluids. Blood and semen are by far the major transmission fluids.', 'role': 'assistant'}]