How can a user track memory usage in an EC2 instance?
A. Call Amazon CloudWatch to retrieve the memory usage metric data that exists for the EC2 instance.
B. Assign an IAM role to the EC2 instance with an IAM policy granting access to the desired metric.
C. Use an instance type that supports memory usage reporting to a metric by default.
D. Place an agent on the EC2 instance to push memory usage to an Amazon CloudWatch custom metric.