Final answer:
The required element for creating Data Driven Pages in GIS is a sort field, which determines the order of pages generated from a single map document based on an attribute in the index layer's attribute table.
Step-by-step explanation:
The element required for creating Data Driven Pages in a GIS (Geographic Information System) is B. sort field. Data Driven Pages allow users to generate a series of layout pages from a single map document where each page is focused on a different spatial extent. A sort field is a necessary attribute within a layer that defines how the pages will be ordered, whether sequentially by an attribute like page number or alphabetically by name. The sort field typically corresponds to a field in the attribute table of the index layer, which is used to define the extent of each page.
It's important to have a sort field because it controls the navigation through the Data Driven Pages, allowing the user to create a coherent set of pages for a report or a map book in a logical order. Spatial reference, page number, and rotation are also settings that can be applied to Data Driven Pages, but they are not required to create them.