question: Q:A 29-year-old Mediterranean man presents to the clinic for fatigue and lightheadedness for the past week. He reports an inability to exercise as his heart would beat extremely fast. He was recently diagnosed with active tuberculosis and started on treatment 2 weeks ago. He denies fever, weight loss, vision changes, chest pain, dyspnea, or bloody/dark stools. A physical examination is unremarkable. A peripheral blood smear is shown in figure A. What is the most likely explanation for this patient’s symptoms?? 
  {'A': 'Abnormally low level of glutathione activity', 'B': 'Drug-induced deficiency in vitamin B6', 'C': 'Hereditary mutations of beta-globin', 'D': 'Inhibition of ferrochelatase and ALA dehydratase', 'E': 'Iron deficiency'},