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': 'A patient presents with mediastinal mass with sheets of epithelial cells giving arborizing pattern of reactivity on keratin, along with interspersed lymphoid cells. The most probable diagnosis is: \nSelect and explain. \nA. Thymoma, B. Thymic carcinoid, C. Primary mediastinal lymphoma, D. Non-Hodgkin lymphoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: . Thymoma', 'role': 'assistant'}]