Which key function allows users to return to a previous function in Bloomberg?

The Esc Key is the correct choice because it serves a vital function in the Bloomberg terminal interface, allowing users to return to the previous screen or menu they were viewing. This key is essential for navigation, enabling users to backtrack through their actions without needing to start over from the home screen or re-enter parameters.

Using the Esc Key is a common practice when a user wants to exit a particular function or command, saving time and streamlining the workflow. The other keys listed do not provide the same navigational capability specific to returning to the last function; for instance, the Home Key usually brings the user back to the main dashboard, the Backspace Key is primarily for text deletion, and the Enter Key is used to execute commands rather than navigate backward. Therefore, the functionality of the Esc Key in navigating the Bloomberg terminal makes it the most effective option for returning to prior functions.