This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oesophagus, Subject name: Medicine
[{'content': "Barrett's esophagus causes which cancer: \nSelect and explain. \nA. Adenocarcinoma, B. Squamous cell CA, C. Carcinoid tumor, D. Esophageal leiomyoma", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. (a) AdenocarcinomaRef: Harrison's 17th ed. Ch. 286* Metaplastic columnar epithelium develops during healing of erosive esophagitis with continued acid reflux since columnar epithelium is more resistant to acid- pepsin damage than is squamous epithelium.* The metaplastic epithelium has different epithelial types, including goblet cells and columnar cells.* Finding intestinal metaplasia with goblet cells in the esophagus is diagnostic of Barrett's esophagus; this type of mucosa is thought to be at risk of cancer", 'role': 'assistant'}]