What is the least likely etiology of AA’s pancytopenia from the history? A. Parvovirus B19 infection B. Posthepatitis aplasia C. Benzene exposure during his years working in a petroleum plant D....

What is the least likely etiology of AA’s pancytopenia from the history?

A. Parvovirus B19 infection

B. Posthepatitis aplasia

C. Benzene exposure during his years working in a petroleum plant

D. Fanconi anemia

E. Undiagnosed sickle cell trait with new overlying cytomegalovirus infection compromising already compromised hematopoietic capacity