This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
Poor prognostic factor for ALL is 
Select and explain. 
A. Female sex, B. Leukocyte factor < 50,000, C. Age greater than 1 year, D. Hypodiploidy
D: Hypodiploidy
Answer: D: Hypodiploidy 
Explanation: Hypodiploid acute lymphoblastic leukemia is the chromosome mutation of leukemic cells with 45 chromosomes or less. It has been determined that the prognosis of hypodiploid is much less than standard acute lymphoblastic leukemia. The lower the chromosome count, the lower the survival rate.