A project has four activities: A$,$ B$,$ C$,$ D$.$ Their durations are $4,3,6,$ and $7$ days, respectively. What is the total completion time for the project?

A project has four activities: A$,$ B$,$ C$,$ D$.$ Their durations are $4,3,6,$ and $7$ days, respectively. What is the total completion time for the project?

$7$ days, because this is the maximum activity time

It is not possible to determine the total completion time from the given information because the connections among the activities are unknown.

$20$ days, because this is the sum of the activity times

$3$ days, because this is the minimum activity time