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
Aplastic anemia can progress to -a) AMLb) Myelodysplastic anemiac) Pure red cell aplasiad) Paroxysmal nocturnal hemoglobinuriae) Myelofibrosis 
Select and explain. 
A. acd, B. bcd, C. abd, D. ab
C: abd
Answer: C: abd 
Explanation: Aplastic anemia is a pancytopenia with bone marrow hypocellularity. It can progress to –

Paroxysmal Nocturnal hemoglobinuria
Myelodysplastic anemia
Rarely acute leukemia

Pure red cell aplasia is a selective disease of absence of erythrocyte progenitor cells. In contrast to aplastic anemia and MDS, the unaffected lineage (WBC and platelets) appear quantitatively and qualitatively normal.
Myelofibrosis is a clonal disorder of a multipotent hematopoietic progenitor cell of unknown origin and is characterized by

Marrow fibrosis
Myeloid metaplasia with extramedullary erythropoiesis
Splenomegaly