Final answer:
Auto Scaling uses CloudWatch to monitor application performance and automatically adjust capacity. CloudWatch provides insights to optimize resource utilization and get a unified view of operational health.
Step-by-step explanation:
Auto Scaling is a feature that can be enabled through several services on the Amazon Web Services (AWS) platform. However, based on the options provided in your question, the correct answer is b) CloudWatch.
Auto Scaling uses CloudWatch to monitor the performance of applications and automatically adjusts the capacity to maintain steady and predictable performance at the lowest possible cost. CloudWatch provides data and actionable insights to monitor applications, understand and respond to system-wide performance changes, optimize resource utilization, and get a unified view of operational health.
In contrast, CloudFront is a content delivery network, Virtual Private Cloud (VPC) enables you to launch AWS resources into a virtual network that you've defined, and Route 53 is a scalable Domain Name System.
Learn more about Auto Scaling