Final answer:
The correct spatial query tool for selecting features based on their relationship to other features is 'Select by location'. This tool allows for different kinds of spatial comparisons such as intersections and proximity.
Step-by-step explanation:
When trying to select features in a geographic information system (GIS) based on their relationship to other features, the spatial query tool to use is Select by location. This allows you to identify features in one layer that have a certain spatial relationship (such as intersecting, within, or containing) with features in another layer. For instance, one might select all houses (features) that are within a certain distance of a floodplain (other features) through this method. Although nearest neighbor analysis is an interesting tool in spatial statistics, which helps measure the clustering of points, it isn't a selection tool but rather an analytical one to assess patterns.