What appears on the timeline when you drag and drop a scene?

When dragging and dropping a scene onto the timeline, a vertical line appears to indicate precisely where you plan to drop the scene. This visual cue helps ensure that users can accurately see their intended placement within the storyboard, offering immediate feedback about where the new scene will be positioned relative to existing content. The use of this vertical line enhances precision during the editing process, allowing for more effective organization and arrangement of scenes in the storyboard.

The other options, while relevant to the overall functionality, do not describe the specific visual feedback provided when dragging a scene. A horizontal line might be related to other features but is not used for scene placement. Similarly, indicators for scene length and duration relate to how a scene is managed once it's placed, whereas alerts about scene conflicts would come into play under different circumstances, such as when there are overlaps or other issues during the placement process.