A Linux service on EC2 runs out of memory while its CPUUtilization metric remains low. Operations needs alarms for memory usage and filesystem utilization without changing the application. Which approach provides these metrics?

1. Install and configure the CloudWatch agent with memory and disk metrics, and grant its instance role permission to publish them.
2. Enable EC2 detailed monitoring and create alarms against the default EC2 memory and filesystem metrics.
3. Create a metric-math expression that converts CPUUtilization directly into free memory and disk space.
4. Enable EC2 status checks and alarm on StatusCheckFailed as the memory-utilization percentage.