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: Physiology
[{'content': 'T cells mature in: March 2012 \nSelect and explain. \nA. Thyroid, B. Tongue, C. Thymus, D. Trachea', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans: C i.e. Thymus Immunologically incompetent cells which go to the thymus are "preprocessed" there (thymus) and become T cells. The letter T comes from the word thymus.', 'role': 'assistant'}]