How do you know if you and another person are working on a shared presentation at the same time?

A) The Co-authoring icon appears in the status bar.
B) The Share button is highlighted in the title bar.
C) The Collaborate button appears on the ribbon.
D) IThe Co-authoring pane opens in the PowerPoint window.

The Co-authoring icon appears in the status bar when multiple people are working on the same presentation at the same time. This icon indicates that real-time collaboration is enabled and that changes made by each co-author are being synced in real-time. The other options mentioned in the question (B, C, and D) are not necessarily indicators of real-time collaboration. The Share button in the title bar is used to invite others to collaborate on a presentation, while the Collaborate button on the ribbon is used to access a range of collaboration features, including commenting and version history. The Co-authoring pane that opens in the PowerPoint window provides information about who is currently working on the presentation, but it does not necessarily indicate that they are working on the presentation at the same time as you.