$19.$ Project planning entails developing estimates for work effort, duration, costs, people, and physical resources. As projects evolve estimates can change and life cycle phases can impact which four aspects associated with estimating:

a$.$ Progressive Elaboration, WBS$,$ Process Groups and Range.

b$.$ Precision, Range, Confidence and Accuracy

c$.$ Range, Accuracy, Rolling Wave and Confidence.

d$.$ Earned Value, Risk Management, WBS and Process Groups.