A 65-Year-Old Guy Arrives to the Workplace Because of Four

A 65-year-old guy arrives to the workplace because of four months of deteriorating weariness. Even doing small home tasks makes the sufferer feel exhausted. He smokes 15 packs a year and drinks 2 or 3 beers every day. Blood pressure is 134/86 mm Hg, temperature is 37 C (98.6 F) , and pulse is 76 beats per minute. Physical examination indicates a mild S2 and a late systolic ejection murmur. Auscultation reveals that the lungs are clean. Hepatosplenomegaly is absent, and the abdomen is smooth and nontender. No specific neurological impairments exist. According to laboratory tests, the mean corpuscular volume is 93 m³ and hemoglobin is 9 g/dL. Below is a peripheral blood smear: Which of the following best explains the observed erythrocyte findings in this patient?

A) Chronic gastrointestinal blood loss
B) Excessive cold agglutinin production
C) Increased serum paraproteins
D) Mechanical erythrocyte injury
E) Nutritional vitamin B₁₂ deficiency