Final answer:
The primary purpose of Roosevelt's words was to encourage collective action against economic hardship and later, during the war, to emphasize America's strength and resilience through a sense of shared responsibility and fortify confidence in the nation's abilities.
Step-by-step explanation:
Through his inaugural address and fireside chats, President Franklin D. Roosevelt's primary purpose was to convey optimism, inspire unity, and restore confidence during challenging times. Roosevelt deployed an emotional and motivational rhetoric to impress the public, but the overarching goal was to engage and propel them into collective action against the economic hardships of the Great Depression and later, the mobilization for World War II. His use of familiar language and direct appeal to American citizens served to fortify the strength of the nation through a sense of shared responsibility and courage.
Within the historical context provided, option C) Convince the public of America’s strength is the most appropriate answer as Roosevelt sought to emphasize the collective power and resilience of the American people and the nation, rather than simply impress or encourage enlistment in the military.