The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 45-year-old woman comes to the physician because of a 2-week history of painful ulcers in her mouth. Over the past 2 months, she has had increasing fatigue and difficulties concentrating. She has a history of rheumatoid arthritis and was started on a new medication 4 months ago. Examination shows pallor of the mucosal membranes and three tender ulcerative lesions in her mouth. Her hemoglobin concentration is 8.7 g/dL and mean corpuscular volume is 109 μm3. A blood smear shows hypersegmented neutrophils. Which of the following is the most likely cause of this patient's findings?   (A) Deficient heme synthesis   (B) Deficient erythropoietin secretion   (C) Deficient nitrogenous base production   (D) Deficient β-globin chains
['(C) Deficient nitrogenous base production <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Deficient heme synthesis \n (B) Deficient erythropoietin secretion \n (C) Deficient nitrogenous base production \n (D) Deficient β-globin chains <> possible answers', "  A 45-year-old woman comes to the physician because of a 2-week history of painful ulcers in her mouth. Over the past 2 months, she has had increasing fatigue and difficulties concentrating. She has a history of rheumatoid arthritis and was started on a new medication 4 months ago. Examination shows pallor of the mucosal membranes and three tender ulcerative lesions in her mouth. Her hemoglobin concentration is 8.7 g/dL and mean corpuscular volume is 109 μm3. A blood smear shows hypersegmented neutrophils. Which of the following is the most likely cause of this patient's findings? <> context@"]