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: Medicine
[{'content': "Direct Coomb's test detects \nSelect and explain. \nA. Antibodies attached to RBC surface, B. Antibodies in the serum, C. Antigens attached to RBC surface, D. Antigens in the serum", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Antibodies attached to RBC surface", 'role': 'assistant'}]