In ASP.NET Core, configuration data can be obtained from various sources using configuration providers. These providers can read data from environment variables, command-line arguments, JSON files, XML files, and more. So, the correct answer is "Configuration providers."

.NET CLI (Command-Line Interface) is a command-line tool primarily used for .NET operations. It allows developers to perform tasks like building, testing, and publishing .NET applications directly from the command line, making it a versatile tool for developers who prefer command-line interfaces.

The .NET Core CLI (Command-Line Interface) plays a crucial role in ASP.NET Core development. It allows developers to interact with their projects through the command line, facilitating tasks like project creation, building, testing, and running. It's a powerful tool for automating development tasks and managing ASP.NET Core projects efficiently.

Docker is a popular containerization tool that can be used with ASP.NET Core for deployment. Docker containers encapsulate the application and its dependencies, making it easy to deploy and run consistently across different environments.

To restrict an action method to respond only to HTTP POST requests in ASP.NET Core MVC, you can decorate the method with the [HttpPost] attribute. This attribute ensures that the method can only be invoked when an HTTP POST request is made to its associated URL.

If an action within a controller with [Authorize] should be accessible without authorization, you can use the [AllowAnonymous] attribute. This attribute allows you to exempt specific actions from the global authorization policy, making them accessible to all users, even if other parts of the controller require authorization.

When the dotnet command is used without any additional arguments, it displays the help menu for the .NET CLI. This menu provides a list of available commands and options, helping developers navigate and use the CLI effectively. It's a handy way to explore the CLI's capabilities and understand how to use various commands and options.

In this scenario, Azure App Service would be the best fit. Azure App Service is a platform-as-a-service (PaaS) offering that abstracts much of the infrastructure management. It allows you to easily deploy and scale web applications without the overhead of managing virtual machines or container orchestrators like AKS.

Visual Studio is a comprehensive Integrated Development Environment (IDE) specifically designed for .NET development. It provides powerful tools and features for building various types of .NET applications, making it a popular choice among developers.

To achieve a redirection after a successful action, you should use the Redirect action result. It allows you to specify the URL to which the user should be redirected, typically a confirmation page in this case. The Redirect result returns an HTTP 302 status code, indicating a temporary redirect.