An adolescent client with iron deficiency anemia has been experiencing extreme fatigue in spite of supplementation with ferrous sulfate. Which question by the nurse is most important?
1. "Are you taking an iron supplement in the morning or at night?" 2. "How long have you been on a vegetarian diet?"
3. "Is your iron supplement taken as a capsule or a chewable?"
4. "Do you take the iron supplement on a full or empty stomach?"