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
Which of the following mechanism can not prevent Gastroesophageal reflux - 
Select and explain. 
A. Looping fibres of crus of diaphragm, B. Mucosal folds at gastroesophageal junction, C. Circular muscle fibres of GE sphincter, D. Angle made by the oesophagus with stomach
C: Circular muscle fibres of GE sphincter
Answer: C: Circular muscle fibres of GE sphincter 
Explanation: Ans is 'c' ie Circular muscle fibres of GE I am not really sure of the answer. When this question was asked, 22/e, of Bailey was in circulation. According to it, among all the given options, circular muscle fibres of GE sphincter appears to be least contributory in preventing reflux. Read these lines of Bailey 22nd ed. " There is a functional intrinsic physiological sphinctre at the cardia. This is expressed as a zone of relatively high intraluminal pressure which prevents regurgitation from the stomach. This impoant function is augmented by five factors : 1. The valvular effects of oesophagogastric angle. 2. The pinchcock action of the right crus. 3. The 'rosette-like' folds of the gastric mucous membrane at the cardia. 4. The presence of a length of intra abdominal oesophagus. 5. A band of muscles on the fundus of the stomach, acting as a sling, which accentuates the esophagogastric angle."