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: Surgery
Investigation of choice for diagnosing intra abdominal bleeding in an unstable patient: September 2007 
Select and explain. 
A. CT scan omit, B. MRI scan, C. USG, D. Diagnostic peritoneal lavage
C: USG
Answer: C: USG 
Explanation: Ans. C: USG