Through which one of the following models does SaaS support multiple users and…

Concept: Tenancy describes how a SaaS provider shares application instances and data among its customers. Under single-tenancy, each customer (“tenant”) gets a completely separate, dedicated application instance and its own dedicated database — nothing is shared. Under multi-tenancy, one running instance of the application serves many customers at the same time, and all of them share the same underlying infrastructure and a common data schema, with each tenant's records kept logically separate (for example, via a tenant-identifier column).

Application: The question describes a SaaS model that supports multiple users while offering one shared data model — that is exactly the definition of multi-tenancy, so multi-tenancy is the correct choice.

Cross-check: Single-tenancy and a “multiple-instance” deployment (a separate instance per customer or group) both keep each customer's data in its own isolated store rather than in one common schema, so neither matches a description built around a shared data model — confirming multi-tenancy is the only fit.