This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
[{'content': 'Length of male urethra \nSelect and explain. \nA. 3-5 cm, B. 5-10 cm, C. 10-15 cm, D. 15-20 cm', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The male urethra measures, on average, 18-20 cm in length. It commences at the internal urethral orifice in the trigone of the bladder and opens in the navicular fossa of the glans penis at the external urethral meatus, which is the narrowest pa of the urethra. ref - BDC vol2 pg376', 'role': 'assistant'}]