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
Most antibodies are produced in the: 
Select and explain. 
A. Heart and the liver, B. Brain and the meninges, C. Thymus and the appendix, D. Spleen and the lymph nodes
D: Spleen and the lymph nodes
Answer: D: Spleen and the lymph nodes 
Explanation: None