Final answer:
The positive accomplishment of FDR's New Deal was the improved infrastructure, which included programs that greatly enhanced the nation's physical landscape and provided the framework for economic stability and recovery.
Step-by-step explanation:
When evaluating the legacy of FDR's New Deal, c) Improved infrastructure is considered a positive accomplishment. The New Deal influenced future generations of Americans by setting the stage for federal involvement in economic regulation and social welfare. This intervention included initiatives that built buildings and bridges, developed national parks, and provided benefits like social security and minimum wage standards. Such programs improved the nation's physical framework and supported economic recovery and stability, which contributed to the postwar economic boom in the 1950s.