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': 'On clinical examination a 60 years old female had a tumor in the right buccal mucosa. The size of the tumor was about 2 cm in diameter. There was no involvement of regional lymph nodes and also had no distant metastasis. The TNM stage of the tumor is: \nSelect and explain. \nA. T1 No Mo., B. T1 N1 Mo., C. T1 N2 Mo., D. T2 No Mo.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]