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
[{'content': 'Mononuclear phagocytes are produced by - \nSelect and explain. \nA. Thymus, B. Spleen, C. Bone marrow, D. Liver', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The monocyte is formed in the bone marrow and transpoed by the blood ; it migrates into the tissues, where it transforms into a histiocyte or a macrophage. Reff: Ananthanarayanan & Panikers textbook of microbiology 9th edition pg:137', 'role': 'assistant'}]