B & C is right

AB
SCRUM GUIDE:
The Scrum Master serves the Scrum Team in several ways, including:

Coaching the team members in self-management and cross-functionality;

Helping the Scrum Team focus on creating high-value Increments that meet the Definition of Done;

Causing the removal of impediments to the Scrum Team’s progress; and,

Ensuring that all Scrum events take place and are positive, productive, and kept within the timebox.

The Scrum Master serves the Product Owner in several ways, including:

Helping find techniques for effective Product Goal definition and Product Backlog management;

Helping the Scrum Team understand the need for clear and concise Product Backlog items;

Helping establish empirical product planning for a complex environment; and,

Facilitating stakeholder collaboration as requested or needed.

The Scrum Master serves the organization in several ways, including:

Leading, training, and coaching the organization in its Scrum adoption;

Planning and advising Scrum implementations within the organization;

Helping employees and stakeholders understand and enact an empirical approach for complex work; and,

Removing barriers between stakeholders and Scrum Teams.



The letter C is wrong because is the Development team that take its own decisions, not the Scrum Master....