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: ENT
[{'content': "Which of the following is the feature of schatzki's ring? \nSelect and explain. \nA. Found in lower one third of esophagus at squamocolumnar junction, B. Found in middle one third, C. Found in upper one third, D. Found in entire esophagus", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Found in lower one - third of esophagus at squamocolumnar junction Schatzki's Ring* It occurs at the junction of squamous and columnar epithelium at the lower end of oesophagus and has also been called lower oesophageal ring.* Usually seen in patients above 50 years of age.* Cause is unknown.* Symptomatic patients complain of intermittent dysphagia and some may even present with bolus obstruction.* It may be associated with hiatus hernia.* Treatment is oesophageal dilatation.", 'role': 'assistant'}]