The correct answer is C.
This is a question with more than one right answer. The question is really asking which is MOST important. The easiest way to deal with these questions is to look for the choice that will have the biggest impact on the project. Choice A is important, but look again at choice C. It is a method of recording the change, like choice A, but it is more specific and detailed. Be careful about choices like D. Changes are not bad and should not generally be prevented.
Pass PMP in the First Attempt : PMP Strategy
Revise PMP Concepts: PMP Concepts
Quiz:
20 Questions Challenge
50 Questions Challenge