Ferrous sulfate elixir is prescribed for a client with iron deficiency anemia. Which instruction should the nurse provide this client about taking the liquid medication?

A. Using a straw helps prevent the liquid iron from staining the teeth, which is a common side effect of iron supplements. B. Swallowing the medication undiluted can cause staining of the teeth and may not be recommended for optimal administration. C. Mixing iron with an antacid can interfere with iron absorption, so it is not recommended. D. Taking iron with milk can inhibit its absorption because calcium in milk can bind with iron and reduce its effectiveness.