Which is NOT a prerequisite to start using Copado DX?

The correct answer is that having the CLI (Command Line Interface) installed is not a prerequisite for starting to use Copado DX. Copado DX can be accessed through the web user interface, which allows users to manage and deploy their Salesforce metadata without relying solely on the CLI. This flexibility makes it possible to begin using Copado DX without having the CLI set up.

In contrast, having access to a Dev Hub is important because it enables the creation of scratch orgs necessary for development and testing purposes within Salesforce. An active Salesforce org is also required to utilize Copado DX features since it is built around Salesforce environments. Lastly, having an existing project setup is crucial to properly manage and track changes you want to deploy or version control, which is central to how Copado DX operates.