Which of the following violates best practices for logging levels?

Turning on DEBUG level logging in a production environment is not aligned with best practices. DEBUG logging is typically used during development and testing to provide detailed insights for troubleshooting and diagnosing issues. It generates a high volume of logs, which can lead to performance degradation and increased storage costs. Additionally, the verbosity of DEBUG logs could expose sensitive information, making systems more vulnerable to security risks.

In contrast, the other options adhere more closely to recommended practices. INFO logging can be used for non-critical issues as it provides useful information without flooding the logs with unnecessary details. Logging errors at the ERROR level is appropriate, as it conveys significant issues that require attention without over-stating their severity. Using WARN for issues related to user experience is also acceptable, as it allows developers to be alerted to potential problems that may not be critical but still warrant attention.