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: Unknown
Investigation of choice for hvpertropic pyloric stenosis is- 
Select and explain. 
A. USG, B. X-ray, C. CT, D. MRI
A: USG
Answer: A: USG 
Explanation: Ans. is 'a' i.e., USG