Answer
Adding a third shift of workers would register as a long run adjustment.
Work Step by Step
Adding a third shift of workers would imply that there were only two shifts of workers before, and thus adding a third shift would register as a significant increase in the number of workers in the company, regardless of the size of production. Assuming that worker contracts usually entail long-term contracts and adding an entire shift of workers would imply a large number of workers, this would register as a long run adjustment as it would be extremely costly to terminate so many workers early, and this would significantly impact the financial decisions of the company.
