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
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: Myelodysplastic syndrome refers to a range of blood disorders. They are cancersin which newly created blood cells in the bone marrow do not develop into healthy working blood cells. Myelodysplastic syndrome (MDS) has often been referred to as pre-leukemia or smoldering leukemia. Refer robbins 9/e