Which combination of steps can help the company control and monitor its monthly AWS usage to achieve a cost that is as close as possible to the target amount?

Explanations:

Implementing an IAM policy that requires users to specify a ‘workload’ tag for cost allocation when launching EC2 instances helps track and categorize costs, making it easier to monitor and control AWS usage and expenses based on workload.

AWS Support cannot apply arbitrary limits to the account to prevent users from launching specific instance types. AWS does not offer such granular controls by default for instance types.

Purchasing all upfront Reserved Instances may provide cost savings but does not ensure a predictable monthly AWS spend, as it locks the customer into specific usage commitments. It may not be adaptable to fluctuating usage needs.

Placing conditions in IAM policies to limit the number of instances that users can launch can control usage to some extent but does not directly ensure predictable costs, as users can still exceed their limits if they manage resources improperly.

Defining ‘workload’ as a cost allocation tag in the AWS Billing and Cost Management console allows for effective tracking and reporting of costs per workload, ensuring better cost visibility and management.

Setting up AWS Budgets to alert and notify when a given workload is expected to exceed a defined cost helps proactively monitor and manage costs, providing the company with predictable alerts before excessive spending occurs.