Recently, Miriah Participated in a Study That Was Designed to Determine

Recently, Miriah participated in a study that was designed to determine how much iron is necessary to prevent iron deficiency. Within a few weeks of consuming an iron-free diet, Miriah's red blood cells began to show signs that they lacked iron, and she began to complain about feeling tired. At that point, the researcher added some iron to Miriah's food, so her daily intake of the mineral was 1 mg. After 1 week, the researchers checked the iron content of Miriah's blood, and although it was higher than the earlier value, she still complained about feeling tired. In the weeks that followed, the scientists continued to increase Miriah's iron intake by 1 mg/week and check her for signs and symptoms of iron deficiency. After a week of taking 6 mg of iron/day, she reported feeling like "her old self" and having plenty of energy. Based on this information, the researchers concluded that Miriah's

A) UL for iron was 6 mg, plus 3 mg as a margin of safety.
B) AMDR for iron was 6 mg/day.
C) body required 6 mg iron/day.
D) RDA for iron was 6 mg.