<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 38-year-old man comes to the clinic complaining of recurrent abdominal pain for the past 2 months. He reports a gnawing, dull pain at the epigastric region that improves with oral ingestion. He has been taking calcium carbonate for the past few weeks; he claims that it used to help a lot but its losing its effects now. Laboratory testing demonstrated increased gastrin levels after the administration of secretin. A push endoscopy visualized several ulcers at the duodenum and proximal jejunum. What characteristics distinguish the jejunum from the duodenum?? A: Crypts of Lieberkuhn, B: Lack of goblet cells, C: Lack of submucosal Brunner glands, D: Peyer patches, E: Pilcae circulares,  <response>: This is a clinical vignette describing a 38-year-old man with recurrent epigastric pain that improves with eating, suggesting peptic ulcer disease. He has been taking calcium carbonate as an antacid which was initially helpful but is becoming less effective. Lab testing showed increased gastrin levels after secretin administration, indicating gastrinoma or Zollinger-Ellison syndrome which causes excessive gastric acid secretion leading to peptic ulcers. Endoscopy revealed ulcers in the duodenum and proximal jejunum. The question asks what anatomical features distinguish the jejunum from the duodenum. The duodenum has Brunner glands in the submucosa which secrete alkaline mucus to protect against acid. The jejunum lacks these Brunner glands. Peyer patches are clusters of lymphoid tissue found in the ileum, not jejunum. Crypts of Lieberkuhn, goblet cells, and circular folds pilcae circulares are found throughout the small intestine including duodenum and jejunum.C: Lack of submucosal Brunner glands 