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
Stone formation in Gall bladder is enhanced by all except : 
Select and explain. 
A. Clofibrate therapy, B. Ileal resection, C. Cholestyramine therapy, D. Vagal stimulation
D: Vagal stimulation
Answer: D: Vagal stimulation 
Explanation: Answer is D (Vagal stimulation) Stone formation is enhanced by Truncal vagotomy (not by vagal stimulation).