The quote that shows the author supports the importance of celebrating Labor Day is:
"The vital force of labor added materially to the highest standard of living and the greatest production the world has ever known and has brought us closer to the realization of our traditional ideals of economic and political democracy."
What does this quote emphasize?
This quote emphasizes the importance of labor in creating a prosperous and democratic society. The author recognizes that workers have made significant contributions to the standard of living and quality of life that we enjoy today. They also acknowledge that labor has played a key role in advancing the ideals of economic and political democracy.
The other quotes in the image do not explicitly express support for celebrating Labor Day. Quote B discusses a change in the emphasis and medium of expression of Labor Day celebrations. Quote C describes a change in the character of Labor Day celebrations in recent years. Quote D discusses the coverage of Labor Day addresses in the news media.