The correct answer is A) Through fireside chats on the radio.
President Franklin D. Roosevelt took advantage of the radio as a means to communicate with the American people on a consistent basis. Throughout his presidency, FDR had many of these fireside chats in which he discussed important policies/topics that affected American citizens.
This included the New Deal, the failure of American banks during the Depression, economic recovery, etc. The goal was to be transparent and to help the American public understand the actions he was taking as president. These radio broadcasts became wildly popular and was the first time a president was able to effectively use mass communication to reach a huge audience.