Which of the following are the guidelines for the construction of a network diagram?
1. Each activity is represented by one and only one arrow in the network
2. Two activities can be identified by the same beginning and end events
3. Dangling must be avoided in a network diagram
4. Dummy activity consumes no rime or resource
Select the correct answer the codes given below
(a) 1,2 and 3 (b) 1,3 and 4
(c) 1,2 and 4 (d) 2,3 and 4