Review Question - QID 213444

A 3-year-old boy is brought to the clinic by his parents who are concerned that their son has been having gastrointestinal issues in recent weeks despite no changes to his diet. They note that his cheeks also appear to be more pale than usual. The parents state that due to renovations occurring in their current home, they have been temporarily staying at an apartment in an old building in their neighborhood. A peripheral blood smear is obtained and shows the finding seen in Figure A. Which of the following treatments would be recommended as a first-line agent in this patient?