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
Which among the following is the commonest site of feilisation in uterine tubes? 
Select and explain. 
A. Isthmic, B. Ampulla, C. Infundibulum, D. Interstitial
B: Ampulla
Answer: B: Ampulla 
Explanation: The uterine tubes, or oviducts, or Fallopian tubes are two muscular tubes with considerable mobility, each measuring about 12 cm in length. Each has a funnel-shaped end, the infundibulum, opening into the peritoneal cavity next to the ovary and with a fringe of finger like extensions called fimbriae. The sequence of regions along each tube is as follows: Infundibulum, Ampulla, the longest and expanded area where feilization normally occurs, Isthmus, a more narrow region nearer the uterus, and Uterine or intramural pa, which passes through the wall of the uterus and opens into the interior of this organ. Ref: Mescher A.L. (2010). Chapter 22. The Female Reproductive System. In A.L. Mescher (Ed), Junqueira's Basic Histology: Text & Atlas, 12e.