Network planning (PERT/ CPM/PDM) methods _
题型：单项选择题
问题：
Network planning (PERT/ CPM/PDM) methods ______.
A) are usually too complicated for practical use on most projects
B) require highly trained specialists for effective use
C) always require computer support to be practical
D) are based on flow charts and they allow observation of what happens to the project schedule when changes occur to a task's start and stop dates
