This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Childhood tumors, Subject name: Pediatrics
Most common malignant tumour in childhood 
Select and explain. 
A. Rhabdomyosarcoma, B. Leukemia, C. Lymphangioma, D. Neuroblastoma
B: Leukemia
Answer: B: Leukemia 
Explanation: Leukemia is the most common malignancy of childhood.There are two main subtypes,the commoner acute lymohoblastic leukemia(ALL) & acute myeloid leukemia(AML).A small propoion may have chronic myeloid leukemia(CML) and juvenile myelomonocytic leukemia(JMML).ALL is the most common childhood malignancy accounting for one-fouh of all childhood cancers. Reference:Essential pediatrics-Ghai,8th edition,page no:599.