Which option must be included in an Azure Resource Manager template to specify the region for a resource group deployment?

When working with Azure Resource Manager templates, specifying the region for a resource group deployment is accomplished through the use of parameters. Parameters allow for the input of values that can be reused throughout the template, making it flexible and adaptable to different deployment environments or scenarios.

In this context, when defining a resource group, the region can be parameterized by including a parameter in the template. This enables the template to be deployed in any region supported by Azure by simply providing the appropriate parameter value at deployment time. Thus, through parameters, you can maintain a clean configuration management process while also avoiding hard-coded values that could limit the template's usability across different regions.

Utilizing parameters also enhances the readability and maintainability of the template, as anyone reviewing the template can quickly identify configurable settings like the region. By having a dedicated parameter for region, developers and administrators can quickly adapt deployments to various geographic locations based on project needs or regional compliance requirements.