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
[{'content': "Most common cause of hematochezia in children is \nSelect and explain. \nA. Rectal polyp, B. Meckel's diveiculum, C. Necrotizing enterocolitis, D. Acute gastritis", 'role': 'user'}, {'content': "Answer: B \nExplanation: Serious causes of hematochezia in the neonate include necrotizing enterocolitis and midgut volvulus. A wide variety of causes of hemorrhage occur as children grow older. Causes relatively unique to children are intussusception, Meckel's diveiculum, and juvenile polyps Ref Davidson edition23rd pg 809", 'role': 'assistant'}]