President Franklin D. Roosevelt's primary response to the Supreme Court's opposition to New Deal legislation was to propose a plan known as "court packing," which involved adding more justices to the Supreme Court to create a more favorable alignment for his policies. This proposal aimed to allow him to appoint additional justices who would support his New Deal programs.
However, some of the options you've provided are not accurate in the context of Roosevelt's response. For example, there was no initiative called the "Court Reduction Act," nor did Roosevelt pass an amendment explicitly limiting judicial power as a direct response to the Court's actions.
Therefore, the correct and most significant response described is the proposal to "add more justices to the Court called 'Court Packing.'" While some may argue about funding or other means, those were not the primary actions Roosevelt took in response to the Court's opposition. Thus, the correct answer among the provided options would focus on the court packing proposal rather than stating that "all of these answers are correct."