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: Medicine
[{'content': 'The most common lymph node group involved in Tb lymphadenitis is : \nSelect and explain. \nA. Posterior cervical, B. Axillary, C. Intraabdominal, D. Jugulodigastric', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Lymph node TB presents as painless swelling of the lymph nodes, Most commonly at posterior cervical and supraclavicular sites are involved. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 1346', 'role': 'assistant'}]