The scenario requires a reporting solution for a distributed team in a 24/7 Continuous Integration (CI) environment. The key requirements are automated reporting for every build, 24/7 availability, and access for the entire team.
Option A is the best solution. A dashboard provides a centralized, "pull-based" information radiator that is accessible anytime, which is ideal for a distributed team. Storing results without overwriting is essential in CI to track the history of build quality, identify trends, and diagnose regressions over time. This approach directly fulfills all the stated requirements in the most efficient manner.

B. Overwriting results from previous builds is a critical flaw. It prevents any historical analysis or trend tracking, which is a primary benefit of automated reporting in a CI pipeline.
C. While it correctly preserves historical data, sending an email for every build (multiple times a day) would create significant "notification spam," making it difficult for team members to track and consume the information effectively.
D. This option is too narrow. The requirement is for "automation test results," whereas this focuses only on code coverage, which is just one quality metric and not the complete test execution result.

1. ISTQB® Certified Tester Advanced Level Test Automation Engineer Syllabus Version 2019.

Section 4.2.2, Monitoring and Reporting (page 31): This section states, "The reports should be easily accessible and provide the necessary information in a clear and concise way. The reports should also show trends over time, for example, the pass/fail rate of the automated test cases." This supports the use of a dashboard for accessibility and the need to store historical data (not overwrite) to show trends.

2. Humble, J., & Farley, D. (2010). Continuous Delivery: Reliable Software Releases through Build, Test, and Deployment Automation. Addison-Wesley Professional.

Chapter 5, The Deployment Pipeline (page 98): The authors emphasize the importance of visibility in the CI/CD process. "The single most important characteristic of a deployment pipeline is that it provides visibility into the production readiness of your application... Everybody in the team should be able to see the current status of any application." A dashboard is a primary tool for achieving this level of visibility, far superior to email reports.