Which holiday celebrates the contributions of workers in the U.S.?

Labor Day is the holiday that specifically celebrates the contributions of workers in the United States. It was established to honor the labor movement and the social and economic achievements of American workers. Observed on the first Monday of September, Labor Day serves as both a tribute to the strength and dignity of workers and a reminder of the importance of worker rights and conditions.

In contrast, Memorial Day is a day of remembrance for those who have died in military service, Independence Day commemorates the adoption of the Declaration of Independence, and Veterans Day honors all military veterans. None of these holidays are focused on the contributions of workers in the same way that Labor Day is, which is why Labor Day is the correct answer.