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': 'Following statements regarding ulcerative colitis is true- ( \nSelect and explain. \nA. Smoking has a protective effect, B. Smoking does not have a protective effect, C. There is no relation to smoking, D. Smoking causes relapses', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ulcerative colitis Inflammation invariably involves the rectum (proctitis) and spreads and also has some bleeding and proximally in a continuous manner to involve the entire colon in some cases (pancolitis). In long-standing pancolitis, the bowel can become shoened and post-inflammatory 'pseudopolyps' develop; these are normal or hyperophied residual mucosa within areas of atrophy . The inflammatory process is limited to the mucosa and spares the deeper layers of the bowel wall . Both acute and chronic inflammatory cells infiltrate the lamina propria and the crypts ('cryptitis'). Crypt abscesses are typical. Goblet cells lose their mucus Ref Davidson edition23rd pg 815", 'role': 'assistant'}]