According to the Scrum Guide 1 , the Development Team consists of professionals who do the work of delivering a potentially releasable Increment of "Done" product at the end of each Sprint. Development Teams are structured and empowered by the organization to organize and manage their own work. The resulting synergy optimizes the Development Team's overall efficiency and effectiveness. Cross-functional teams have all competencies needed to accomplish the work without depending on others not part of the team.
The team model in Scrum is designed to optimize flexibility, creativity, and productivity.
References: Scrum Guide

The correct answers are B and D. The Scrum Master is accountable for the Scrum Team's effectiveness and helps the team improve its practices within the Scrum framework. One important way this happens is by facilitating Scrum Team decisions. That makes Option B correct. The Scrum Master does not make decisions for the team, but helps create the conditions for effective collaboration, self-management, and sound decision- making. This support improves the team's ability to inspect, adapt, and work productively.
Option D is also correct because the Scrum Master serves the Scrum Team by causing the removal of impediments to the Scrum Team's progress. Impediments reduce flow, create delays, and lower effectiveness.
By helping remove those obstacles, the Scrum Master enables the team to focus on creating valuable Increments.
Option A is incorrect because ordering the Product Backlog is the Product Owner's accountability, not the Scrum Master's. Option C is too narrow. While the Scrum Master helps ensure Scrum events are positive, productive, and within the timebox, simply starting and ending meetings on time is not one of the two primary ways they help maximize team productivity. Their deeper contribution is enabling effectiveness and removing barriers.

The correct answer is B because as a Scrum Team matures, it is expected to strengthen its quality standards and improve its Definition of Done. The Scrum Guide explains that the Definition of Done creates transparency by making clear what it means for work to be complete. As the team becomes more capable, disciplined, and technically proficient, it often raises those standards to ensure higher quality, greater releasability, and more dependable Increments.
This improvement reflects empirical learning. A mature Scrum Team does not become less Scrum-like. It usually becomes more effective at applying Scrum. That means the team may refine engineering practices, strengthen testing, improve integration, and include more rigorous completion criteria in the Definition of Done.
Option A is incorrect because timeboxes do not expand simply because a team matures. Option C is incorrect because the Scrum Master remains accountable for Scrum effectiveness even with a mature team. Option D is incorrect because the Sprint remains a fixed timebox and a core element of Scrum. Option E is incorrect because Sprint Reviews continue to be essential for inspection and adaptation with stakeholders.

According to the Scrum Guide, estimates are made by the people doing the work, which is the Development Team. The Development Team is responsible for all estimates in the Product Backlog and the Sprint Backlog.
The other options are not valid guidelines for estimating work in Scrum, as they are either too prescriptive (such as requiring story points or relative units), incorrect (such as forbidding estimating or having the Product Owner make estimates), or unnecessary (such as checking estimates with the Development Team).

According to the Scrum Guide, two characteristics of the Daily Scrum are its location and time remain constant and its purpose is to inspect progress toward the Sprint Goal and adapt the Sprint Backlog. These characteristics promote consistency, transparency, and adaptation within the Development Team. The other options are not valid characteristics of the Daily Scrum, as they are either irrelevant (such as being held first thing in the morning) or inappropriate (such as being free form, facilitated by the team lead, or consisting of the Scrum Master asking for status).