A company's application ingests data from multiple SaaS sources. The company uses Amazon EC2 instances to receive the data and upload it to an Amazon S3 bucket for analysis. The same EC2 instances also send a notification to the user when an upload completes. The company has observed slow application performance and wants to improve it as much as possible with the least operational overhead. Which solution meets these requirements?

The correct solution leverages Amazon AppFlow to directly transfer data from SaaS sources to S3, eliminating the need for EC2 instances in the ingestion path. This significantly reduces operational overhead and improves performance by removing the EC2 bottleneck. S3 event notifications are then used to trigger an SNS topic upon upload completion, decoupling the notification process from the ingestion. The other options are less optimal: Creating an Auto Scaling group for EC2 instances addresses scaling but doesn't remove the EC2 bottleneck for data ingestion, still incurring operational overhead for managing instances. Using Amazon EventBridge for each SaaS source is more complex and requires configuring multiple rules, increasing operational overhead compared to AppFlow. EventBridge is generally used for event-driven architectures, not direct data transfer from SaaS to S3. Replacing EC2 with Docker containers on ECS still involves managing compute resources and doesn't directly address the efficiency of data ingestion from SaaS sources, adding complexity rather than simplifying. CloudWatch Container Insights is for monitoring, not for sending upload completion notifications.