A 52-year-old man has a diagnosis of aplastic anemia. Which information in the patient history is pertinent to this diagnosis?

A. Long family history of cancer: Aplastic anemia is a bone marrow failure disorder, not typically a hereditary cancer, though it can lead to leukemia. B. 25-year employee in a chemical plant: Aplastic anemia can be "acquired" through exposure to environmental toxins, such as benzene and certain insecticides or chemicals found in industrial settings. C. Regular blood donor: Regular blood donation might lead to iron deficiency, but it does not cause the bone marrow to stop producing all three blood cell lines (pancytopenia). D. Gain of 5 lb in the last 2 years: Weight gain is not a clinical indicator or risk factor for the development of aplastic anemia.