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: Microbiology
[{'content': 'Most antibodies are produced in the: \nSelect and explain. \nA. Heart and the liver, B. Brain and the meninges, C. Thymus and the appendix, D. Spleen and the lymph nodes', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]