This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc. (W.B.C), 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. Myelodysplastic syndrome
B: Paroxysmal cold hemoglobinuria
Answer: B: Paroxysmal cold hemoglobinuria 
Explanation: Ans. (b) Paroxysmal cold hemoglobinuria(Ref: Wintrobe's 12th/pgchap 78)Paroxysmal nocturnal hemoglobinuria (PNH), Aplastic anemia & Myelodysplastic syndrome predispose to Leukemia