Final answer:
Option D best captures the central idea of the speech that the success of the United States is not complete if poverty among its citizens prevents the full exercise of personal liberty.The correct option is D.
Step-by-step explanation:
Among the options provided, the one that best identifies the central idea of the speech is D.
The United States cannot be considered a success if some of its citizens live in poverty, since those conditions do not allow for personal liberty.
The materials provided discuss the economic prosperity the United States enjoyed after World War II, the spread of American businesses and the American dollar's dominance post-war.
However, they also highlight the domestic challenges, including the fair treatment of ethnic minorities and women, the desire for ongoing economic prosperity, and the right to equal opportunities, which is a cornerstone of the American Dream.
The speech emphasizes that without addressing the issue of poverty and ensuring that all citizens have the opportunity to live free from want, the nation's success is incomplete.The correct option is D.