This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
B cell maturation takes place in - 
Select and explain. 
A. thymus, B. Lymph node, C. Bone marrow, D. Spleen
C: Bone marrow
Answer: C: Bone marrow 
Explanation: The key cells in our immune system are lymphocytes known as B cells and T cells, which originate in our bone marrow. After T cells fuher develop in our thymus. Reff: www.mayoclinic.com