Correct Answer - Option 2 : 3 only
An activity is an actual performance of the task which requires both time and cost resources for its completion. Ex: Excavation, casting of beam, erection of turbines are some activities.
Characteristics of an activity in a network are:
1. An activity lies between two nodes. Number of nodes increase as the activity progresses.
2. Length of arrow has no significance in an activity.
3. An activity can start only when its tail event occurs.
4. An activity cannot occur more than once in the network.
Concurrent activities:
1. They can be completed simultaneously.
2. They can shorten the duration of project.
3.
They are mutually independent i.e. delay in one activity does not affect the completion of another activity.