Upon adding a dataset to an existing map, an analyst receives a warning that the spatial reference is unknown. Which process will resolve this issue?

When a dataset is added to a map and the spatial reference is indicated as unknown, defining the coordinate system of the feature class is essential to ensure spatial alignment with other layers in the map. By assigning the coordinate system of the feature class to match that of the data frame, the analyst provides a clear spatial reference for the data, which enables accurate mapping and analysis.

This approach resolves the issue by establishing a known spatial reference, thereby facilitating subsequent operations and ensuring that the dataset integrates seamlessly into the existing map environment. If the coordinate systems do not align, features may appear in incorrect locations or not display at all.

The other processes may not effectively resolve the unknown spatial reference problem directly. For instance, simply importing the feature class into a file geodatabase does not inherently define or clarify its spatial reference. Adding the feature class to a data frame with a Geographic Coordinate System or projecting it to match the data frame could address alignment issues, but without first defining the spatial reference of the feature class itself, these actions may not be sufficient for ensuring accurate representation. Thus, defining the coordinate system of the feature class is the most straightforward and effective solution to this problem.