A project manager had originally planned to use both of the company's industrial $3$D printers simultaneously for the training mock$-$up project but has just learned that one of them will be unavailable. The project manager adjusts the schedule so that the components are created sequentially using the one remaining $3$D printer. Unfortunately, this action affects the critical path and delays the planned finish date of the project. What tool or technique has the project manager used in this situation?

Group of answer choices

Crashing

Resource smoothing

Fast tracking

Resource leveling