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: Answer is A (Antibodies attached to RBC Surface) Direct Coomb's test detects IgG Antibodies (or complements) attached to the surface of RBCs. Indirect Coomb's test detects IgG antibodies in the serum (e.g. Anti-D Antibodies).", 'role': 'assistant'}]