Which installation method uses an answer file to automate responses without user intervention?

The installation method that uses an answer file to automate responses without user intervention is an unattended installation. This method involves creating a file that contains predefined answers to the prompts normally encountered during a setup process. By using this answer file, the installation can proceed automatically without requiring any input from the user, which is particularly useful for deploying operating systems in large environments where user interaction would be impractical.

Other methods like a factory recovery partition or clean installation do not generally incorporate an answer file for automation. A factory recovery partition typically restores the system to its original state using preset configurations without the need for an installation file. A clean installation involves manually installing an operating system, often requiring direct user input throughout various steps. Resetting your PC may allow for some options to restore or refresh the operating system, but this process still typically involves user choices and confirmation prompts. Hence, unattended installation is specifically designed for automation, making it the correct choice.