This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oral Cavity, Subject name: ENT
[{'content': 'Radiographic findings of cardiac achalasia include all except: \nSelect and explain. \nA. Oesophageal dilatation, B. Rat-tail appearance, C. Failure of lower oesophageal sphincter to relax, D. Diffuse oesophageal spasm', 'role': 'user'}, {'content': 'Answer: D \nExplanation: In cardiac achalasia, there is lack of lower oesophageal sphincter to relax with consequent dilatation of oesophagus. Radiologically dilated oesophagus and spasm of lower oesophageal sphincter gives a "rat-tail" or "bird-beak" appearance. Primary achalasia is associated with idiopathic degeneration of ganglion cells of the Auerbach\'s plexus.Secondary cardiac achalasia is caused by:(i) . Carcinoma of distal oesophagus(ii) . Chaga\'s disease(iii) . Post-vagotomy syndrome(iv) . Cerebrovascular accident(v) . Diabetes.', 'role': 'assistant'}]