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: Gynaecology & Obstetrics
[{'content': 'All except one is true regarding fallopian tube \nSelect and explain. \nA. Fertilization occurs in ampullary portion of fallopian tube, B. There are no longitudinal muscle fibres in interstitial portion of tube, C. It has 2 sources of blood supply, D. Isthmus in narrower portion of fallopian tube.', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Interstitium is narrowest portion of fallopian tube.', 'role': 'assistant'}]