This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: Medicine
[{'content': 'Cut off for diagnosis of Priapism is? \nSelect and explain. \nA. 1 hours, B. 2 hours, C. 3 hours, D. 4 hours', 'role': 'user'}, {'content': 'Answer: D \nExplanation: - Priapism is a pathological painful erection of penis more than 4 hr. - Causes: An excessive release of neurotransmitters Blockage of draining venules (e.g., mechanical interference in sickle cell crisis, leukemia, or excessive use of intravenous parenteral lipids) Paralysis of the intrinsic detumescence mechanism Prolonged relaxation of the intracavernous smooth muscles (most often caused by the use of exogenous smooth-muscle relaxants such as injectable intra-cavernosal prostaglandin E1).', 'role': 'assistant'}]