Which of the following is NOT the way for project managers to stay on schedule $($Refer to the assigned article "Four ways project managers can stay on schedule" in Ch$5$ website$)$

Question $4$ options:

Add slack time into the project time schedule

Maintain the critical path of the project

Avoid crashing $($e$.$g$.$ reducing the completion time for tasks in the critical path$)$ by any means.

Utilize the fast track tasks when necessary