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
Chemotherapy can be successful during treatment of: 
Select and explain. 
A. Anneloblastoma, B. Leukemia, C. Fibrosarcoma, D. Basal cell carcinoma
B: Leukemia
Answer: B: Leukemia 
Explanation: None