Which statement best supports long-term maintainability of code?

• A. Use extensive ad-hoc documentation only
• B. Rely on the original developer to remember decisions
• C. Try to minimize comments and documentation
• D. Use clear structure, comments, tests, and documentation

Answer: (D)

Maintaining code over the long term works best when the codebase is organized, easy to understand, and safeguarded against regressions. A clear structure helps future developers quickly locate and modify the right parts of the system. Comments explain why decisions were made and what edge cases or trade-offs to consider, not just what the code does. Tests verify that behavior stays correct as changes happen, making refactoring safer. Documentation provides context such as setup instructions, dependencies, and design rationale, so new contributors can get up to speed without relying on memory or past conversations.

Ad-hoc documentation tends to be incomplete or out of date, making it hard to rely on. Relying on the original developer’s memory is dangerous because people move on or forget details. Minimizing comments and documentation removes essential context, making future maintenance slower and more error-prone.