Answer:
(d) not possible to tell from information given
Explanation:
You want to know the total completion time for a project with four activities that take 4, 3, 6, and 7 days.
Completion time
The project completion time will be determined by the dependencies between activities.
Series
If each activity must be completed before the next, then the total time will be 4+3+6+7 = 20 days.
Parallel
If there are no dependencies and all activities can be done in parallel, then the total completion time is 7 days, the time required for the longest activity.
In short, it is not possible to determine the total time from the information given.