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: Radiology
Best investigation to diagnose a hydatid cyst in liver is ? 
Select and explain. 
A. Ultrasound, B. CT-scan, C. MRI, D. MRCP
B: CT-scan
Answer: B: CT-scan 
Explanation: Ans. is 'b' i.e., CT-scanFor hydatid cyst1st line investigation - UltrasoundInvestigation of choice - CT-scan