Which AWS service should be used to monitor Amazon EC2 instances for (CLF-C02)

Correct answer: C) Amazon CloudWatch.
Amazon CloudWatch provides data and actionable insights to monitor your applications, understand and respond to system-wide performance changes, optimize resource utilization, and get a unified view of operational health. It collects monitoring and operational data in the form of logs, metrics, and events, providing a reliable, scalable, and flexible monitoring solution. For monitoring EC2 instances specifically, CloudWatch can track metrics such as CPU utilization and network traffic, allowing you to set alarms and notifications based on these metrics.