So torn with this question. Mainly because:
Once the SDLC reached the development phase, code starts to be generated. That means that the ability to control the version of the software or component that your team is working on, combined with check-in/check-out functionality and revision histories, is a necessary and powerful tool when developing software.
The question refers to a "new" product so I believe that is key. However, it also makes it seem that it is about the development of a product that could be in production.
Regression testing focuses on testing to ensure that changes that have been made do not create new issues, and ensure that no new vulnerabilities, misconfigurations, or other issues have been introduced.
Hmmm, I say C simply because of the "new product" in the question.