In creating a new water distribution network, what must an ArcGIS user create to manage fire hydrant laterals and service water pipes within one feature class?

To manage fire hydrant laterals and service water pipes within one feature class in ArcGIS, creating subtypes is essential. Subtypes enable the categorization of features within a single feature class, allowing for the organization and classification of features based on specific attributes. In the context of a water distribution network, subtypes can differentiate between fire hydrant laterals and service water pipes, enabling users to apply different rules, symbology, and behaviors to each subtype.

By setting up subtypes, the user can manage these related features effectively while keeping them contained within a unified feature class. This structured approach enhances data management and ensures that the various attributes and functionalities pertinent to each feature type can be maintained, ensuring the integrity and usability of the data within the GIS environment.

While other options like relationship rules, coded value domains, and connectivity rules serve significant purposes in data management and relationships, they do not provide the same level of direct categorization and classification of different features within a single feature class as subtypes do.