This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oral cavity & Oesophagus, Subject name: ENT
[{'content': 'All of the following are Hypomotility disorders of oesophagus except \nSelect and explain. \nA. Nut cracker oesophagus, B. Achalasia cardia, C. Gastroesophageal reflux, D. Scleroderma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: MOTILITY DISORDERS OF OESOPHAGUS They can be divided into: 1. Hypermotility disorder:- e.g. cricopharyngeal spasm, diffuse oesophageal spasm, nut cracker oesophagus. 2. Hypomotility disorders:- e.g. cardiac achalasia, gastrooesophageal reflux, scleroderma, amyotrophic lateral sclerosis. Ref:- Dhingra; pg num:-344', 'role': 'assistant'}]