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': 'Tumour with perineural invasion: \nSelect and explain. \nA. Adenocarcinoma, B. Adenoid cystic Ca, C. Basaal cell ca, D. Squamous cell ca', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans is 'b' ie Adenocystic Ca", 'role': 'assistant'}]