Explanation/Reference:

Detailed Explanation & Reference from Scrum
Scrum Guide Reference:
"The Sprint Backlog is composed of the Sprint Goal (why), the set of Product Backlog items selected for the Sprint (what), as well as an actionable plan for delivering the Increment (how)."
"The Sprint Backlog is a plan by and for the Developers. It is a highly visible, real-time picture of the work that the Developers plan to accomplish during the Sprint in order to achieve the Sprint Goal."
Why is "C. The Developers" Correct?
The Sprint Backlog is owned and managed by the Developers because they are the ones responsible for planning and executing the work.
The Developers update and modify the Sprint Backlog as needed during the Sprint.
The Scrum Team collaborates during Sprint Planning to define the Sprint Backlog, but the ongoing responsibility for managing it lies only with the Developers.
This allows the team to self-manage and adapt as work progresses.
❌ Incorrect Answers with Explanations
❌ A. The Scrum Team
Why is this Incorrect?
While the Scrum Team (Scrum Master, Product Owner, and Developers) collaborates during Sprint Planning, only the Developers are responsible for the Sprint Backlog.
The Scrum Master does not manage the Sprint Backlog, and the Product Owner does not modify it once the Sprint starts.
❌ B. The Scrum Master
Why is this Incorrect?
The Scrum Master facilitates the process but does not own or manage the Sprint Backlog.
The Scrum Master helps the team understand Scrum practices and remove impediments, but they do not decide or change the Sprint Backlog.
❌ D. The Product Owner
Why is this Incorrect?
The Product Owner is responsible for the Product Backlog, NOT the Sprint Backlog.
Once a Sprint starts, the Product Owner cannot modify the Sprint Backlog-only the Developers can update it as they learn more.

According to the Scrum Guide1, ordering Product Backlog items is solely up to the Product Owner's discretion. The Product Owner orders items in the Product Backlog to best achieve goals and missions. To do this, they optimize value by considering various factors such as cost and benefit, risk, dependencies, date needed, etc. The Product Owner is responsible for maximizing the value of the work the Development Team does. The Scrum Master is accountable for establishing Scrum as defined in the Scrum Guide. They do this by helping everyone understand Scrum theory and practice, both within the Scrum Team and the organization. Therefore, an appropriate action for the Scrum Master to take if the Product Owner is struggling with ordering the Product Backlog is to offer the Product Owner help in understanding that the goal of ordering the Product Backlog is to maximize value.

According to the Scrum Guide1, self-organization is one of the essential characteristics of Scrum Teams. Self-organizing teams choose how best to accomplish their work, rather than being directed by others outside the team. Self-organization enables teams to deliver faster and better results by harnessing their creativity and skills. Some benefits of self-organization are:
Increased creativity, as team members have more freedom and autonomy to explore new ideas and solutions.
Increased self-accountability, as team members take ownership and responsibility for their work and outcomes.
Increased commitment, as team members are more engaged and motivated by having a say in how they work.
The other options are not benefits of self-organization, as they may imply external control or pressure.