<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 1-year-old previously healthy male presents to the emergency department with 3 hours of intermittent abdominal pain, vomiting, and one episode of dark red stools. On exam, his abdomen is tender to palpation and there are decreased bowel sounds. A CT scan reveals air fluid levels and a cystic mass in the ileum. Gross specimen histology reveals gastric tissue. What is the cause of this patients problems?? A: Obstruction of the lumen of the appendix by a fecalith, B: Abnormal closure of the vitilline duct, C: Twisting of the midgut secondary to malrotation, D: Hypertrophy of the pylorus, E: Ingestion of contaminated water,  <response>: This is a clinical vignette describing a 1-year-old male with abdominal pain, vomiting, dark stools, tenderness on abdominal exam, decreased bowel sounds, and imaging findings of air-fluid levels and an ileal cystic mass. Histology revealed gastric tissue. The key findings here are the patients young age, imaging revealing a cystic mass in the ileum, and histologic confirmation of ectopic gastric tissue. This clinical presentation is most consistent with an intestinal duplication cyst containing ectopic gastric mucosa, which can ulcerate and cause bleeding.Choices A and E can be eliminated, as a fecalith causing appendiceal obstruction or contaminated water ingestion would not explain the ileal cystic mass or ectopic gastric tissue. Choice D of pyloric hypertrophy also does not fit with the ileal location. Choice C of intestinal malrotation is plausible, as it can be associated with midgut volvulus and bowel obstruction. However, it would not directly explain the presence of a cystic mass or ectopic gastric tissue.Therefore, choice B, abnormal closure of the vitelline duct, is the most likely diagnosis. This can result in a Meckels diverticulum, which is a remnant of the vitelline duct that can contain ectopic gastric mucosa and lead to the findings described.B: Abnormal closure of the vitilline duct 