Final answer:
The United States pursued motives in Southeast Asia through a combination of military intervention, such as in the Philippine-American War, and economic strategies such as the Open Door notes in China. The Taft Commission's reforms also played a role, suggesting that the U.S. employed a mix of diplomatic, economic, and military tactics.
Step-by-step explanation:
At the turn of the twentieth century, the United States pursuit of interests in Southeast Asia included a mix of strategies but was notably marked by military intervention and the fostering of economic interests. The U.S. engaged in the Philippine-American War, applying military force to establish control over the Philippines.
This was part of a broader trend of U.S. imperialism, in which the country was increasingly looking to expand its influence economically, politically, and militarily in regions like Southeast Asia.
The United States also applied economic measures, such as the Open Door notes, to ensure access to Chinese markets, highlighting the use of economic clout over direct military force at times.
Due to these varied approaches—coupled with political negotiations and reforms like those introduced by the Taft Commission in the Philippines that aimed to modernize local governments and infrastructure—the correct answer to the student's question would be option b) The United States pursued its motives in Southeast Asia through diplomatic negotiations and trade agreements.