The Village Green, a Woman's Clothing Store, Took a Map

The Village Green, a woman's clothing store, took a map of the city and the cheques written by its customers during the last quarter. The store's owner then marked the address of each customer on the map with a map pin. By looking at where the pins clustered on the map, she could determine her trade area. She was engaged in:

A) customer clustering
B) geographic research
C) residential research
D) primary research
E) customer spotting