What development allowed the american economy to be affected by economic problems in other regions of the world?

The correct answer is: "globalization and market integration"

Economic globalization has involved market integration. Both have possible due to improvements in both transport and communications technologies. Many trade barriers have dissapeared and many markets of goods, services and factors of production function at an international or global level.

The US participates in integrated markets and this is why its economy is affected by problems which have arisen in other regions of the world.

are their options?

otherwise i can't

the answer wold be b) travel among nations should be regulated by an international organization