A Lambda function must run automatically at the end of each day to produce a report from data stored in Amazon S3. What is the MOST operationally efficient way to schedule this Lambda invocation?

The most operationally efficient way to schedule a daily Lambda invocation is by using an Amazon EventBridge (CloudWatch Events) rule with a schedule expression. EventBridge allows you to define schedules using cron or rate expressions, directly invoking the Lambda function at the specified time without needing additional infrastructure. This approach is serverless, highly available, and requires minimal operational overhead. Creating an EventBridge rule that matches S3 events is incorrect because the requirement is to run the function at the end of each day, not in response to S3 object changes. Configuring an S3 event notification would also trigger the Lambda function based on S3 object changes, which doesn't meet the daily schedule requirement. Hosting an EC2 instance with a cron job is less operationally efficient as it introduces server management overhead (patching, monitoring, scaling) and additional cost compared to a fully managed serverless solution like EventBridge.