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: ENT
The lower esophageal sphincter (LES) resting pressure is: 
Select and explain. 
A. 5-10 mm Hg, B. 10-15 mm Hg, C. 15-25 mm Hg, D. None of the above
C: 15-25 mm Hg
Answer: C: 15-25 mm Hg 
Explanation: The LES measures 3-4 cm in length and its resting pressure ranges between 15 and 24 mm Hg. At the time of swallowing, the LES relaxes for 5-10 seconds to allow the food bolus to enter the stomach, and then it regains its resting tone