1. The problem asks for the total duration of the entire project based on the Gantt chart. 2. The Gantt chart shows tasks scheduled across weeks labeled W1, W2, W3, W4 for three months. 3. The earliest task starts at W1 of the first month (Project Kickoff). 4. The latest task ends at W4 of the third month (Commissioning). 5. Since the tasks span from the first week of the first month to the last week of the third month, the total duration is 3 months. 6. Therefore, the entire task is scheduled for 3 months. **Final answer:** 3 months