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: Medicine
Massive bleeding per rectum in a 70years patient is seen most commonly in 
Select and explain. 
A. Carcinoma, B. Colitis, C. Diveiculosis, D. Polyps
C: Diveiculosis
Answer: C: Diveiculosis 
Explanation: Hemorrhage from a colonic diveiculum is the most common cause of hematochezia in patients >60 years, yet only 20% of patients with diveiculosis will have gastrointestinal bleeding. Patients at increased risk for bleeding tend to be hypeensive, have atherosclerosis, and regularly use aspirin and nonsteroidal anti-inflammatory agents. Most bleeds are self-limited and stop spontaneously with bowel rest. The lifetime risk of rebleeding is 25%.Reference: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 353; Diveicular Disease and Common Anorectal Disorder