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
Gall bladder adenocarcinoma is only involving lamina propria. What is the  preferred treatment 
Select and explain. 
A. Simple cholecystectomy, B. Radical cholecystectomy, C. Chemotherapy alone, D. Radiotherapy
A: Simple cholecystectomy
Answer: A: Simple cholecystectomy 
Explanation: Only invading lamina propria is T1a stage -simple cholecystectomy.