The concept of infrastructure as code (IaC) is to define and manage infrastructure using code, rather than manual processes or GUI tools. A script that contains a series of public cloud CLI commands is an example of IaC, because it uses code to provision resources into a public cloud. The other options are not examples of IaC, because they involve manual or interactive actions, such as running curl commands, sending REST requests, or entering commands into a console. References = [Introduction to Infrastructure as Code with Terraform] and [Infrastructure as Code]

Detailed Explanation:
* Rationale for Correct Answer (B):The file() function reads a file from disk and returns its content as a string. This is commonly used for public keys (.pub files).
* Analysis of Incorrect Options:
* A. fileset(): Returns a set of filenames matching a pattern, not file contents.
* C. filebase64(): Reads file and returns Base64 encoded string - unnecessary for .pub.
* D. templatefile(): Used for rendering templates with variables, not raw file contents.
* Key Concept:Terraform's file() function is used for injecting file content directly.
Reference:Terraform Exam Objective - Read, Generate, and Modify Configurations.

This is how Terraform chooses which version of the provider to use, when you add a new resource to an existing Terraform configuration, but do not update the version constraint in the configuration. The lock file records the exact version of each provider that was installed in your working directory, and ensures that Terraform will always use the same provider versions until you run terraform init -upgrade to update them.

This is what will happen if you run terraform destroy without any flags, as it will attempt to delete all the resources that are associated with your current working directory or workspace. You can use the -target flag to specify a particular resource that you want to destroy.

All of the statements are true of Terraform providers. Terraform providers are plugins that enable Terraform to interact with various APIs and services1. Anyone can write a Terraform provider, either as an individual or as part of a community2. HashiCorp maintains some providers, such as the AWS, Azure, and Google Cloud providers3. Cloud providers and infrastructure vendors can also write, maintain, or collaborate on Terraform providers, such as the VMware, Oracle, and Alibaba Cloud providers. References =
*1: Providers - Configuration Language | Terraform | HashiCorp Developer
*2: Plugin Development - How Terraform Works With Plugins | Terraform | HashiCorp Developer
*3: Terraform Registry
*: Terraform Registry