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
The most sensitive test to detect GI bleeding is ? 
Select and explain. 
A. Selective angiography, B. Radiolabelled, erythrocyte scanning, C. Fibrinogen studies, D. Stool for occult blood
B: Radiolabelled, erythrocyte scanning
Answer: B: Radiolabelled, erythrocyte scanning 
Explanation: Ans. is 'b' i.e., Radiolabelled, erythrocyte scanning