Which of the following should be enabled when you want a user at another Mac to take control of your computer?

The correct answer is Screen Sharing. This feature allows users on another Mac to view and take control of your Mac's screen, facilitating collaboration or remote assistance. When Screen Sharing is enabled, it provides the remote user access to your screen, enabling them to interact with applications and files on your system as if they were physically present.

Remote Desktop typically refers to a broader service that may include Windows systems, allowing for remote connections with more extensive capabilities, but it is not specific to Mac environments. Remote Assistance is a term often associated with Windows and provides a way for experienced users to assist others, which may confuse its applicability in a Mac context. Screen Mirroring allows for the duplication of a display to another screen (often used with projectors or Apple TV) but does not provide the capability for remote control of the computer.

Each of these alternatives serves distinct purposes, but for enabling another user on a Mac to take control of your computer, Screen Sharing is the precise feature required.