The company is nearing its EC2 instance service quota and needs an automatic alert when utilization of that quota reaches 70% so scaling issues can be addressed. Which approach provides the most operationally efficient way to get this notification?

The most operationally efficient approach is to use the Service Quotas console to create a CloudWatch alarm. AWS Service Quotas natively integrates with CloudWatch, allowing you to directly create alarms for service utilization metrics, including EC2 instance count. This method requires minimal setup and maintenance, as AWS manages the underlying data collection and metric generation. Creating a Lambda function to manually check quotas is less efficient because it introduces unnecessary operational overhead. You would need to write, deploy, and maintain the Lambda code, manage its permissions, and configure an EventBridge schedule. While technically possible, it's not the recommended or most efficient solution when a native integration exists. Monitoring CPUUtilization of an Auto Scaling group is irrelevant to the EC2 instance service quota. CPU utilization measures the performance of existing instances, not the total number of instances provisioned against a service limit.