A nurse is reviewing the complete blood count results for a 4-year-old child who is receiving treatment for acute lymphoblastic leukemia. Which of the following findings should indicate to the nurse that the treatment is having a therapeutic effect?

A. A platelet count of 98,000/mm3 is below the normal range, indicating thrombocytopenia, which is common in leukemia but not indicative of therapeutic response. B. In the context of ALL, a high WBC count often reflects the presence of malignant lymphoblasts rather than healthy, mature infection-fighting cells. A therapeutic effect would ideally show the WBC count returning to a normal range. C. In ALL, the bone marrow is infiltrated by leukemic cells, which suppress normal blood cell production, including red blood cells (RBCs). Effective chemotherapy reduces leukemic cells and allows normal RBC production to recover, so an RBC count within the normal range (here, 5/mm³) indicates the bone marrow is responding to treatment. Platelets and WBCs may still be low or elevated due to chemotherapy effects or transient bone marrow response, but RBC recovery is a direct sign of marrow recovery and therapeutic effect. D. A hemoglobin level of 6.8 g/dL is low, indicating anemia, which is common in leukemia and its treatment but is not an indication of therapeutic effect.