This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Anatomy
Best investigation for ureteric stones is: 
Select and explain. 
A. CT, B. CECT, C. USG, D. IVP
A: CT
Answer: A: CT 
Explanation: Helical CT without oral or intravenous contrast is the preferred imaging modality for patients with renal colic or suspected urolithiasis" -- Smith's Urology Ref : Smith's Urology 17/e p81, 261