The correct answer is B) National security.
The other options of the question were A) Free trade. C) Regulated banking. D) Worker protection.
The main goal of America's foreign policy is designed to achieve is "National security."
The national security of the country is the number one priority of the United States foreign policy. That is why -through history- the United States government has protected his interests in other countries to the extreme to participate in wars or send troops to territories where the security of the US interests are threatened. Inland, after the terrorist attacks of September 11, 2001, the Bush Administration ordered the creation of the Department of Homeland Security to protect the United States of another attack.