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: Surgery
[{'content': 'Most common site of urethral carcinoma in men is: \nSelect and explain. \nA. Penile urethra, B. Bulbomembranous urethra, C. Prostatic urethra, D. Fossa nevicularis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: "The bulbomembranous urethra is involved most frequently, accounting for 60% of tumors, followed by the penile urethra (30%) and the prostatic urethra (10%)."- Campbell-Walsh Urology 9th ed. Chapter 32\nCarcinoma of the male urethra is rare.\nEtiologic factors include chronic inflammation due to a history of frequent sexually transmitted diseases, urethritis, and urethral stricture, and there is likely to be a causal role for human papillomavirus 16 in squamous cell carcinoma of the urethra.\nThe most common presenting symptoms are urethral bleeding, a palpable urethral mass, and obstructive voiding symptoms.\nMost common site is:\n\nbulbomembranous urethra (60%)\npenile urethra (30%)\nprostatic urethra (10%).\n\nMost common histological subtype is:\n\n\nsquamous cell carcinoma (85%)\n\n\ntransitional cell carcinoma (15%).', 'role': 'assistant'}]