<prompt> A patient of more than 70 years, presented with generalized lymphadenopathy, WBC count was 20,000mm3 and blood film showed 70 mature looking lymphocytes. Next investigation that should be done -LN BiopsyPeripheral ImmunohistophenotypingBone marrow aspirationPeripheral blood cytogenetics  <response>: . Peripheral Immunohistophenotyping 