The nurse recognizes that which definitive diagnostic study is performed for Hodgkin's lymphoma?

A. Genetic testing for Philadelphia factor is used in chronic myeloid leukemia, not Hodgkin's lymphoma. B. Urine study for Bence Jones proteins is related to multiple myeloma diagnosis. C. Serology for Human T-cell Virus-1 (HTLV-1) is associated with adult T-cell leukemia/lymphoma, not Hodgkin's lymphoma. D. Lymph node biopsy is the definitive diagnostic study for Hodgkin's lymphoma, identifying the presence of Reed-Sternberg cells.