This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
[{'content': "Barrett's esophagus is \nSelect and explain. \nA. Lower esophagus lined by columnar epithelium, B. Upper esophagus lined by columnar epithelium, C. Lower esophagus lined by ciliated epithelium, D. Lower esophagus lined by pseudo stratified epithelium", 'role': 'user'}, {'content': "Answer: A \nExplanation: Barrett's esophagus is specialized columnar metaplasia that replaces the normal squamous mucosa of the distal esophagus in some persons with GERD. Barrett's epithelium is a major risk factor for adenocarcinoma of the esophagus and is readily detected endoscopically, due to proximal displacement of the squamocolumnar junction.Ref: Harrison; 19th edition; Page no: 1895", 'role': 'assistant'}]