Which of the following Visual Studio projects contains the Startup.cs class?

The Startup.cs class is a crucial component typically found in ASP.NET Core applications. It plays a key role in application configuration and is responsible for defining the services that the application will use and the application's request handling pipeline.

The RenderingHost project is specifically designed to serve as a host for rendering Sitecore components on the front end, thereby making it appropriate for the usage of Startup.cs. It manages the initialization of the application's services and middleware which are essential for rendering content dynamically, especially for headless setups.

In contrast, other projects such as MyProject, Platform, and ContentManagement may contain various features and functionalities related to Sitecore, but they are not primarily focused on the core hosting aspects and configurations that the RenderingHost project embodies. This distinction is what makes the RenderingHost project the appropriate choice for containing the Startup.cs class.