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: Pathology
[{'content': 'The thick mucous coat is - \nSelect and explain. \nA. Protective in ulcer patients, B. Not protective in ulcer patients, C. Easily destroyed by antacids, D. Commonly associated with carcinomatous change', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Surface mucus layer acts as a defensive force and protects against peptic ulceration.', 'role': 'assistant'}]