Setup and configurations are controlled by the TMS administrator and are inherited down the hierarchy using the _______ rule.

The correct answer is the 80/20 rule. In the context of Transportation Management Systems (TMS), this principle suggests that a significant portion of the effects or outputs (typically around 80%) comes from a relatively small percentage of causes or inputs (around 20%). When it comes to setup and configurations within a TMS, it means that the administrator's configurations will typically cover the majority of the common scenarios and setups, allowing for efficient management of the system.

By applying the 80/20 rule to the hierarchy, it ensures that standard configurations, which cater to the most common requirements, are inherited down through the different levels of the hierarchy. This streamlines processes and maintains consistency across various segments of the organization. The focus on the most impactful configurations helps to minimize complexity and management overhead, which is essential in a robust TMS environment.

The other options do not accurately describe the model for hierarchical inheritance in TMS setups. Waterfall refers to a project management approach that is linear and sequential. SCRUM is an agile framework for managing projects, emphasizing iterative progress and collaboration. Legacy typically describes older systems or practices that may still be in use, rather than a model for configuration inheritance.