Which of the Following Is True of Treating Iron Deficiency

Which of the following is true of treating iron deficiency?

A) Anemia caused by a nutritional lack of iron cannot be treated with oral iron supplements.
B) Vitamin C should not be used in combination with iron supplements in the treatment of iron deficiency as it reduces the intestinal absorption of iron.
C) Iron dextran (INFeD) can be used to treat iron deficiency in patients who have impaired gastrointestinal absorption.
D) Long-term iron-deficient patients should be treated with 20 to 50 mg of iron per day for at least 6 months.