This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
Normal lower oesophageal sphincter pressure is 
Select and explain. 
A. 5-8 mm of Hg, B. 10-25 mm of Hg, C. 25 - 40 mm of Hg, D. > 40 mm of Hg
B: 10-25 mm of Hg
Answer: B: 10-25 mm of Hg 
Explanation: The normal lower oesophageal sphincter is 3-4 cm in length and has a pressure of 10-25 mmHgThe LOS is a zone of relatively high pressure that prevents gastric contents from refluxing into the lower oesophagusRef: Bailey and Love 27e pg: 1068