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: Surgery
A 65 years old patient with coronary aery disease was on Aspirin for 2 years. He now complains of black stools. Abdominal examination is normal. What is the most probable diagnosis 
Select and explain. 
A. Ileocecal TB, B. Ca colon, C. Esophageal varices, D. Duodenel ulcer
D: Duodenel ulcer
Answer: D: Duodenel ulcer 
Explanation: Peptic ulcer( 55%)- ulcer bleeding is precipitated by NSAIDs like aspirin. Reference SRB 5th edition page no. 990