Project Sponsor vs Project owner role

I have a question regarding Kaplan E2 2019 syllabus study book page 397 data vs Mock exam A question 53.

The question there says to choose all applicable for a project sponsor:
1. Building a project management team
2. Approving the project budget
3. Communicating the project process to the board of PP
4. Negotiating with subcontractors responsible for software development
5. Monitoring the quality of work within the project
6. Signing off the post-implementation report

I selected only point 2 and the answer was marked as incorrect as I had not selected point 6. In the description, it is described that H is only project sponsor and not also project owner. If H would have both roles then point 6 should have been selected, but H has only one role and in Kaplan book point 6 is marked as project owner role. So how should I understand it? Is there an error on mock exam answer or project sponsor role is also point 6?

Many thanks for the clarification.
RJ