What is the next thing you should do?

Update the project plan to reflect the change-monitoring & controlling. Integration management. The first thing you should do after a change request is approved is to update the project documents. Once the documents are updated, then you can inform the stakeholders. After that you can go back to work and manage the project based on the approved change. Choice a is clearly wrong, because you always analyze the impact of a change prior to submitting a change request (that is likely the first question you will be asked by the CCB - what's the impact to your project?).