Which one of the following statements is TRUE?
◦ The progress chart graphically displays the days each employee is on duty.
◦ Gantt charts display only the ideal use (planned schedules) of resources over time because the actual use is too variable.
◦ The machine chart is a visual tool useful for determining the consequence of schedule changes on a trial-and-error basis.
◦ Gantt charts are tools that determine the optimal schedule of jobs in a job shop.