In Terraform, what is an output value?

An output value in Terraform serves as a mechanism to display and utilize information derived from the infrastructure resources defined within the configuration. When you declare an output value, you specify a piece of data, such as the IP address of a deployed virtual machine or the ARN of a created resource, that you want to easily access after Terraform applies your configurations. This data can be crucial for further integrations or for understanding the state of your infrastructure.

Outputs are particularly useful in multi-module setups where values from one module need to be shared and accessed in another. By defining outputs, you facilitate the communication of essential information across different parts of your Terraform project, thereby enhancing modularity and clarity in your infrastructure as code practices.

Overall, output values are about exposing useful data to users or automated processes, making option C the correct choice.