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: Surgery
[{'content': 'Most impoant pathophysiological cause of GERD is: \nSelect and explain. \nA. Hiatus hernia, B. Transient LES relaxation, C. Hypotensive LES, D. Intermittent changes in LES pressure tone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b. Transient LES relaxation', 'role': 'assistant'}]