The correct answer is C. By enabling AWS X-Ray for all the Lambda functions, you can configure an X-Ray insight on a group that includes all the Lambda functions. This allows you to get detailed insights into the performance of these functions. X-Ray helps you trace requests as they travel through the application and provides a visual map of services, allowing you to identify performance bottlenecks. It also helps in isolating the service where latency or errors are occurring, which is essential for diagnosing issues during high traffic periods.