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': 'Gall bladder adenocarcinoma is only involving lamina propria. What is the  preferred treatment \nSelect and explain. \nA. Simple cholecystectomy, B. Radical cholecystectomy, C. Chemotherapy alone, D. Radiotherapy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Only invading lamina propria is T1a stage -simple cholecystectomy.', 'role': 'assistant'}]