This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Radiology
Ultrasound is not useful in: 
Select and explain. 
A. CBD stones at distal end, B. Breast cyst, C. Ascites, D. Full bladder
A: CBD stones at distal end
Answer: A: CBD stones at distal end 
Explanation: a) CBD stones at distal end of CBD .