In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

Question: Iron deficiency anemia is treated with oral or parenteral preparations: 
 Options:  <1> Only ferrous salts should be used orally. <2> Only ferric salts should be used orally. <3> Orally, the most appropriate form is the iron-dextran complex. <4> Orally, the treatment should last a maximum of fifteen days. <5> Only ferrous salts should be used parenterally.
1