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 of more than 70 years, presented with generalized lymphadenopathy, WBC count was 20,000/mm3 and blood film showed >70% mature looking lymphocytes. Next investigation that should be done - \nSelect and explain. \nA. LN Biopsy, B. Peripheral Immunohistophenotyping, C. Bone marrow aspiration, D. Peripheral blood cytogenetics', 'role': 'user'}, {'content': 'Answer: B \nExplanation: . Peripheral Immunohistophenotyping', 'role': 'assistant'}]