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
Least likely to be Pre-leukemic condition is ? 
Select and explain. 
A. Paroxysmal nocturnal hemoglobinuria, B. Paroxysmal cold hemoglobinuria, C. Aplastic anemia, D. Myelodysplastc syndrome
B: Paroxysmal cold hemoglobinuria
Answer: B: Paroxysmal cold hemoglobinuria 
Explanation: Ans. is 'b' i.e., Paroxysmal cold hemoglobinuria Conditions predisposing to acute leukemia o Myelodysplastic syndrome o Chronic myeloproliferative disorders o Ionizing radiation & ceain toxic chemicals o Bloom syndrome o Fanconi anemia o Paroxysmal nocturnal hemoglobinuria o Li-Fraumani syndrome o Diamond - Blackfan anemia o Ataxia telangiectasia Down syndrome Klinefelter's syndrome o Neurofibromatosis o Aplastic anemia (rarely) Schwachman syndrome Turner syndrome