This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
True about Schatzki&;s ring 
Select and explain. 
A. Has skeletal muscle, B. Located at lower esophagus, C. Causes dysphagia, D. Contain all layers of oesophagus
B: Located at lower esophagus
Answer: B: Located at lower esophagus 
Explanation: SCHATZKI'S RINGS They are semicircular protrusion of lower oesophageal mucosa located at or just above the oesophagogastric junction (squamocolumnar junction). Its under-surface is lined by columnar gastric epithelium. * They involve only the mucosa and submucosa of the oesophagus, not the muscle. * They present with dysphagia and reflux Treatment * Intermittent oesophageal bougienage. * Antireflux drugs .ref: SRB&;s manual of surgery,3 rd ed, pg no 749