The best two answers are A and C.
A. Timeboxing work to allow for frequent inspection. This is a relevant boundary for self-management provided by the Scrum framework, as it helps the Scrum Team to organize their work into fixed-length Sprints and other events, such as the Daily Scrum, the Sprint Planning, the Sprint Review, and the Sprint Retrospective. Timeboxing enables the Scrum Team to inspect their progress, adapt their plan, and deliver value regularly and predictably.
C. Creating a valuable and useful Increment by the end of each Sprint. This is also a relevant boundary for self-management provided by the Scrum framework, as it guides the Scrum Team to focus on delivering a product Increment that meets the Sprint Goal and the Definition of Done. Creating a valuable and useful Increment requires the Scrum Team to collaborate, communicate, and coordinate effectively, and to apply their skills and creativity to solve complex problems.
References:
The Scrum Guide, section 2.3 (The Scrum Team), page 7
The Scrum Guide, section 3.1 (The Sprint), page 8
The Scrum Guide, section 3.4 (The Increment), page 10
The Scrum Master Learning Path, module 2 (The Scrum Framework), lesson 2 (The Sprint), lesson 3 (The Sprint Goal), lesson 4 (Sprint Planning) and lesson 5 (The Sprint Review)
The Professional Scrum Master II (PSM II) Assessment, question 40
