This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
In which of the following conditions uniform dilation of esophagus is seen - 
Select and explain. 
A. Scleroderma, B. Achalasia cardia, C. Dermatomysitis, D. All
B: Achalasia cardia
Answer: B: Achalasia cardia 
Explanation: Ans. is 'b' i.e., Achalasia cardia Achalasia cardia Achalasia cardia is a motor disorder of the esophageal smooth muscle, characterized by ? 1. Aperistalsis 2. Failure of relaxion of the LES with swallowing 3. Increased resting tone of LES