A 74-year-old man comes to the physician because of a 4-month history of weakness and fatigue. Hemoglobin is 10 g/dL, leukocytes 8,000/μL, and platelets 200,000/μL. A peripheral smear is shown. He is a volunteer at a rural nursing home. Which of the following is the most likely explanation for these findings?
Aplastic anemia
β-thalassemia
Diverticulosis
Folate deficiency
Hepatitis C
