Consider the following statements     1. In work break down structure top - down approach is adopted   2. Bar- chart depicts interdependency of activities 3. Controlling can be better achieved in milestones chart ................................................. Which of these statement is/ are correct (a) 1 and 3 only              (b)1and 2 only (c) 2 and 3 only    (d)  1,2 and  3