What events caused the united states to intervene in southwest asia?

The "Anglo-American Petroleum agreement" caused United states to directly involve in the Southwest Asia.

Explanation:

Throughout the history of United States, foreign interventions have been continuous. Interventionism and Isolationism have been the dominant thoughts in United States. Whenever there is a threat to the home country or neighbouring countries, United states played a major role in subsiding the issues. They have been continuously providing a friendly atmosphere whenever required.  The roots of involvement in middle east existed in the first world war. It became much deeper after the second world war. They considered middle east as the strategic area of the world. This is because of the transition of the United States from the net exporter to the net importer of Petroleum in the interests of Middle East.

I'm pretty sure it's c. extremely gradual but not 100% sure though.

Exploration mission 2;