Answer:
The correct answer is option b.
Explanation:
When foreign producers sell their goods and services in the US market they get US dollars in return. They use these dollars to buy goods and services from the US.
If import restrictions prohibit foreigners from selling various goods and services in the U.S. market, foreigners will have fewer U.S. dollars which they can spend to buy U.S. goods and services. So they will be able to purchase fewer goods and services from the US.