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: Pediatrics
7 year old child presented with fever, bleeding gums and fatigue for 4 days. On examination, she had splenomegaly. CBC shows Hb of 6gm%, TLC 75,000/HL, Platelet count 35,000 / HL. Bone marrow aspiration showed these cells as comprising 50% of marrow cells. What is the diagnosis? 
Select and explain. 
A. Infectious mononucleosis, B. Acute leukemia, C. Myelofibrosis, D. Juvenile CML
B: Acute leukemia
Answer: B: Acute leukemia 
Explanation: Image shows, Blast cells. These Blast cells makes more than 50% of bone marrow aspirate. It suggests Acute leukemia.