Comprehensive and Detailed Explanation From Exact Extract:

In Agile development, particularly in Scrum, the Scrum master serves as a facilitator and servant leader for the Scrum team. Their primary responsibility is to guide the team's processes and remove impediments that block progress. The Scrum master ensures that Agile principles and Scrum practices are followed, facilitates key events (such as daily stand-ups, sprint planning, reviews, and retrospectives), and works to improve team collaboration and continuous improvement.

The Scrum master focuses on:

Supporting the team in following agreed processes and timeboxes.

Identifying and removing obstacles that slow or prevent the team from delivering value.

Serving as a bridge between the team and external stakeholders, protecting the team from unnecessary interruptions.

Why the other options are incorrect:

A . Coordinating team logistics and managing external vendors -- While the Scrum master may help facilitate communication, vendor management and logistics coordination are typically project management or operations roles, not the core definition of a Scrum master.

B . Reviewing code and merging development branches -- These are technical responsibilities usually handled by developers or technical leads, not the Scrum master's core role.

D . Monitoring system performance and reporting outages -- This aligns more with operations or DevOps roles; the Scrum master's main focus is team process and impediment removal, not system monitoring.