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: Pathology
[{'content': 'Most common site of peptic ulcer in duodenum - \nSelect and explain. \nA. 1st pa, B. 2"d pa, C. 3rd pa, D. 4th pa', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 1st paPeptic ulcero Ulcers are defined histologically as a breach in the mucosa of the alimentry tract that extends through themucularis mucasea into the submucosa or deep.o Peptic ulcers are chronic , most often solitary lesions that occur in any protion of the gastrointestinal tract exposedto the aggressive action of acid / peptic juice .Peptic ulcers located in the following sits, in order of decreasing frequency : Duodenum, 1' poionStomach ,usally antrumAt the gastro - esophageal junction in the setting of gastroesphageal reflux or Barrett's esophagus.Within the margins of a gastrojejunostomy.In the duodenum, stomach or jeunum of patients with Zollinger -Ellison Syndrome.Within or adiacent to Meckels diveiculum that contains ectopic gastric mucosa.", 'role': 'assistant'}]