For the purposes of rapid response, the term “mass layoff” used throughout this subpart will have occurred when at least one of the following conditions have been met:

(a) A layoff meets the State's definition of mass layoff, as long as the definition does not exceed a minimum threshold of 50 affected workers;

(b) Where a State has not defined a minimum threshold for mass layoff meeting the requirements of paragraph (a) of this section, layoffs affecting 50 or more workers; or

(c) When a Worker Adjustment and Retraining Notification (WARN) Act notice has been filed, regardless of the number of workers affected by the layoff announced.