Hello Sharon,
Sorry, I may not have a straight answer for you, because it is hard for us to give you an explanation without the full context of the exam questions.
Two things I can advise, however:
1. When PMI is designing the exam questions, they want you to pick the best answer out of the 4 choices.
2. Pay attention to what stage the project is in. For instance, you don't need a CR if the project is still in the planning stage.