This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen & Pelvis, Subject name: Anatomy
[{'content': 'A 5-day-old male infant is diagnosed with anorectal agenesis. An ultrasound study reveals a rectourethral fistula. Which of the following is the most likely embryologic cause of this condition? \nSelect and explain. \nA. Failure of the proctodeum to develop, B. Agenesis of the urorectal septum, C. Failure of fixation of the hindgut, D. Abnormal partitioning of the cloaca', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Anorectal agenesis is due to abnormal partitioning of the cloaca and is often associated with a rectourethral, rectovaginal, or rectouterine fistula. Failure of fixation of the hindgut can result in volvulus. Failure of the proctodeum to develop will result in an imperforate anus. Agenesis of the urorectal septum would most likely lead to a fistula but would not cause anorectal agenesis. Premature rupture of the anal membrane would not cause anorectal agenesis.', 'role': 'assistant'}]