Which file type can be dragged and dropped from the desktop directly into the ArcGIS Online map viewer?

The correct answer is the .csv file type. A .csv, or comma-separated values file, is widely recognized as a format for tabular data that can easily be imported into various applications, including ArcGIS Online. When you drag and drop a .csv file into the ArcGIS Online map viewer, the platform processes the data and transforms it into a feature layer, allowing you to visualize and analyze the data effectively.

The other file types listed are not suitable for direct drag-and-drop use in the ArcGIS Online map viewer. A file geodatabase (.gdb) is a proprietary database format used for storing spatial data but cannot be directly dragged and dropped into the map viewer due to its complex structure. Similarly, mpk files, which are map packages created in ArcGIS Desktop, contain a collection of datasets and configurations but need to be published rather than just dragged and dropped. Finally, a shapefile (.shp) is a widely used vector data format, but it comprises multiple required files (not just the .shp file itself) and is not directly supported for drag-and-drop functionality in the ArcGIS Online interface. Thus, the .csv file emerges as the only option that aligns with the drag-and-drop capability in the context of