Which testing technique would be most effective in determining and improving the maintainability of the code?

Selecting static analysis as the most effective technique for determining and improving the maintainability of code is appropriate because static analysis involves examining the code without executing it. This method can identify various issues, such as coding standards violations, complexity metrics, and potential bugs, all of which contribute to maintainability.

By utilizing static analysis tools, developers can get insights into code structure, readability, and adherence to best practices - factors that significantly impact how easy it is to maintain the code over time. These tools can highlight areas of the code that may be overly complex or poorly structured, enabling developers to refactor and improve the codebase proactively.

In contrast, peer reviews can provide valuable feedback on code quality and maintainability but are often subjective and depend on the skills and perspectives of the reviewers. Dynamic testing, while useful for assessing functionality, does not directly address maintainability issues as it focuses on the behavior of the code during execution. Unit testing is crucial for verifying individual components but doesn't comprehensively evaluate issues that could affect maintainability across the complete system.

Thus, static analysis stands out as the most effective technique specifically targeting the maintainability of the code.