The best answer to the question about how U.S. foreign policy today differentiates from foreign policy during the country's founding is:
C. The country's foreign policy has shifted from an isolationism perspective to an internationalism perspective.
During the founding period, the U.S. largely adopted an isolationist stance, aiming to avoid entanglement in European conflicts and focusing on domestic issues. Over the years, especially after World War II, U.S. foreign policy evolved towards a more internationalist approach, actively engaging in global affairs, forming alliances, and promoting democracy and free trade worldwide.