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
[{'content': "Cobble stone appearance is seen in \nSelect and explain. \nA. Ulcerative colitis, B. Crohn's disease, C. Appendicitis, D. Carcinoma rectum", 'role': 'user'}, {'content': "Answer: B \nExplanation: .in crohn&;s disease,Fibrosis, stricture formation, deep ulcers, oedema of mucosa between ulcer areas which looks like 'cobble stone', skipped normal areas in between, serosal opacity, mesen-teric fat stranding, enlarged mesenteric lymph nodes, abscesses in the mesentery, fistula are the pathology. Small mucosal aphthous ulcers are earliest gross feature. ref:SRB&;s manual of surgery,ed 3,pg no 800", 'role': 'assistant'}]