Final answer:
Supporters of Mahan's ideas would favor a foreign policy aimed at spreading American influence, building a strong navy, and establishing overseas markets and strategic bases.
Step-by-step explanation:
Supporters of Alfred Mahan's ideas most likely favored a foreign policy that would spread American influence. Mahan, a U.S. Naval Academy graduate and influential theorist, posited in his works, such as "The Influence of Sea Power upon History, 1660-1783", that a country's greatness was directly linked to its sea power, which encompassed a strong navy, a robust merchant fleet, and overseas colonies for strategic bases and markets. He urged the United States to build up its naval capabilities to protect its economic interests abroad and secure its position as one of the dominant global powers. Advocates for an American empire, including figures like Theodore Roosevelt, were influenced by Mahan's ideology and likely sought to facilitate trade and assert control through military presence in key strategic locations. Therefore, the answer to the question is (a) spread American influence.