During which SDLC phase are Static Code Analysis tools, linters, and automated unit tests used to identify vulnerabilities while writing code?

The correct answer is found during the phase in the Software Development Life Cycle (SDLC) where code is actively being written and can be assessed for security vulnerabilities. Static code analysis tools, linters, and automated unit tests are primarily used during the coding phase to assess the quality and security of the code as it is developed. This proactive approach helps developers identify issues early, ensuring that the code adheres to defined standards and is free from common programming errors or vulnerabilities.

By utilizing static code analysis and other automated testing tools while writing code, teams can reduce the likelihood of introducing security flaws, optimize the code for performance, and streamline debugging. This phase plays a critical role in establishing a secure foundation for the software, allowing for rigorous testing and quality assurance in subsequent phases.

In this context, while the other options mention relevant activities in the SDLC, they do not align with the specific usage of these tools. The testing and quality assurance testing phases focus more on evaluating completed features, while solution design and requirements gathering are about planning and defining what the software will do rather than assessing its actual code.