Final answer:
Fortifying salt with iodine is the best policy to implement in order to improve iodine status.
Step-by-step explanation:
The best policy to implement to improve iodine status, considering cost and efficiency, is to fortify the salt with iodine.
Fortifying salt with iodine has been an effective method to prevent iodine deficiency and goiter in many countries, including the United States. It is a cost-effective and efficient way to ensure the population receives an adequate amount of iodine in their diet.
By adding iodine to salt, it can reach a wide population and can be easily incorporated into daily meals without requiring additional effort from individuals.