Final answer:
The sizes of a sanitary double tee are likely governed by industry-specific standards corresponding to an implied 'Rule of Uniformity' for consistency and compatibility with other plumbing components.
Step-by-step explanation:
The correct rule for describing the sizes of a sanitary double tee is not explicitly listed among the provided options. However, in plumbing and engineering, the correct representation of components like sanitary tees often relies on standards and conventions specific to the industry, such as the Uniform Plumbing Code (UPC) or the International Plumbing Code (IPC), where dimensions and sizes follow certain standardized rules. These could be referred to more broadly under concepts such as the Rule of Uniformity, which ensures that fittings are consistent with industry standards and compatible with other plumbing components. While the provided choices do not directly align with any standard plumbing terminology, the Rule of Uniformity seems like the closest fit conceptually.