For an Activity in a CPM Analysis the Early Finish

Multiple Choice

For an activity in a CPM analysis the Early Finish time is 20 and the Late Finish time is 20.Which of the following statements is ?

A) The activity's late start must happen before its early start
B) The activity is on the critical path
C) The slack for this activity is 20
D) The duration of this task is zero
E) The duration of this task is 20