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: Medicine
[{'content': 'In achalasia cardia, true is: \nSelect and explain. \nA. Pressure at distal end increased with no peristalsis, B. Low pressure at LES with no peristalsis, C. Pressure > 50 mmHg with peristalsis, D. Pressure at the distal end increased with normal relaxation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (Pressure at distal end increased with no peristalsis): Achalasia is characterized by an increased pressure of LES and absence of esophageal peristalsis. Physiological /Manometric features of Achalasia Elevated Resting pressure of LES (>45 mmHg)Q Incomplete LES relaxation (in response to swallowing)Q Absence of distal esophageal peristalsis', 'role': 'assistant'}]