Final answer:
The Worker Adjustment and Retraining Act (WARN) requires employers with more than 100 employees to provide written notice 60 days before plant closings or large layoffs.
Step-by-step explanation:
The Worker Adjustment and Retraining Act (WARN) is a federal law in the United States that requires employers with more than 100 employees to provide written notice 60 days before plant closings or large layoffs. Based on this information, the correct answer to the question is C. Employers with 100 or more employees.