This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gall Bladder & Bile Ducts, Subject name: Surgery
Which of the following is the initial investigation of choice for evaluation of a suspected case of gall stones? 
Select and explain. 
A. Ultrasonography, B. CT Scan, C. MRI, D. ERCP
A: Ultrasonography
Answer: A: Ultrasonography 
Explanation: Ans. is 'a' i.e., Ultrasonography * Transabdominal ultrasonography is the initial imaging modality of choice in patients with suspected gall stones, as it is accurate, readily available, inexpensive and quick to perform