A project manager believes that modifying the scope of the project may provide added value for the customer. The project manager should?

C. Postpone the modification until a separate enhancement project is funded after this project is completed according to the original baseline

In my opinion appropriate choice shall be to change the scope baseline after consulting with stakeholders , project ream & customer.

B. Call a meeting of the configuration control board

Thank you for invitation. I seem option B. Call a meeting of the configuration control board is good answer.