Which button is used to exit PowerPoint's slideshow mode?

In PowerPoint, exiting slideshow mode can be easily accomplished by using the ESC key. When you are in slideshow mode, pressing this key allows you to immediately end the presentation and return to the normal editing view of your slides. This is a standard function across many software applications that utilize full-screen modes, making it intuitive for users to know how to exit out of such modes quickly.

The other choices do not provide a direct way to exit slideshow mode. The new slide button is designed for adding new slides to your presentation and does not facilitate exiting. The reading view button switches the display to a reading format that allows users to view slides without the editing tools, but it does not exit the slideshow. Lastly, the slide sorter button allows you to see a thumbnail view of all slides for reordering and managing slide layouts, not for exiting the slideshow mode. Therefore, using the ESC key is the most efficient and straightforward method to exit a presentation in PowerPoint.