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': 'For early diagnosis of ca stomach which method is used - \nSelect and explain. \nA. Endoscopy, B. Staining with endoscopic biopsy, C. Physical examination, D. Ultrasound abdomen', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Endoscopy with multiple biopsies and brush cytology is the investigation of choice for gastric cancer.', 'role': 'assistant'}]