Stakeholders includes anybody impacted by the project or outcome. You need to break it down to answer your question. Do a stakeholder profile, identifying all of them, then describe their interest. Then you can answer what relationship (and responsibilities, if any) they have with the project. A Sponsor will have certain responsibilities, that will differ from the Project Manager, the customer groups, the permitting agencies, the Subject Matter Experts, the IP holders, and so on. Once you have the Stakeholders profiled, you will also have a good start on the proper methods of communicating with them. The RACI tool in PMBOK might be useful in your situation.