Answer:
The correct answer is the option D: Total project costs are the lowest.
Explanation:
To begin with, when it comes to the business field and the management area, the "project duration" refers basically to the characteristic that the project management has regarding the duration of it, very commonly expressed in terms of working units like hours, days, weeks, months or years for example. Moreover, there are three major types of project duration that are: "Estimated Project Duration", "Actual Project Duration" and "Remaining Project Duration". And to end up, the point where the duration of the project is opmital is when the total project costs are the lowest of all.