This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Ulcerative colitis involves \nSelect and explain. \nA. Serosa, B. Lamina propria, C. Mucosa, D. Circularis muscle', 'role': 'user'}, {'content': "Answer: C \nExplanation: Answer 'c' i.e. Mucosa Ulcerative colitis involves mucosa and superficial submucosa with deeper layers unaffected except in fulminant disease.", 'role': 'assistant'}]