The correct answer is: A. Amazon machine instances are sized at various levels and rented on a computing/hour basis.
Amazon EC2 instances are available in a variety of sizes, from small instances with a single virtual core and 1.75 GB of memory to large instances with 32 virtual cores and 244 GB of memory. Instances can be rented on a monthly or hourly basis.
CloudWatch is a monitoring service that provides metrics, events, and alarms for AWS resources. The metrics obtained by CloudWatch can be used to enable a feature called Auto Scaling, which automatically adjusts the number of EC2 instances in use based on demand.
A number of tools are used to support EC2 services, including the AWS Management Console, the AWS Command Line Interface (CLI), and the AWS SDKs.
Here is a more detailed explanation of each option:
- Option A: Amazon machine instances are sized at various levels and rented on a computing/hour basis. This is incorrect. Amazon EC2 instances are available in a variety of sizes, from small instances with a single virtual core and 1.75 GB of memory to large instances with 32 virtual cores and 244 GB of memory. Instances can be rented on a monthly or hourly basis.
- Option B: The metrics obtained by cloudwatch may be used to enable a feature called auto scaling. This is correct. CloudWatch is a monitoring service that provides metrics, events, and alarms for AWS resources. The metrics obtained by CloudWatch can be used to enable a feature called Auto Scaling, which automatically adjusts the number of EC2 instances in use based on demand.
- Option C: A number of tools are used to support ec2 services. This is correct. A number of tools are used to support EC2 services, including the AWS Management Console, the AWS Command Line Interface (CLI), and the AWS SDKs.
- Option D: None of the mentioned. This is incorrect. Option A is incorrect. Option B is correct. Option C is correct.