In the Adobe Workfront data model, work items are organized hierarchically. A project, as a singular entity, can be associated with only one program and one portfolio at any given time. This ensures clear ownership, reporting, and management alignment. Tasks are child objects of a project; therefore, they inherit the project's association with its parent program and portfolio. This one-to-one relationship (a project to a single portfolio/program) is a fundamental structural constraint within the Workfront system.

A. Projects can exist as standalone entities in Workfront and are not required to be associated with either a program or a portfolio.

C. A project can be associated with a program at any point after its creation; this action is independent of and not contingent upon the existence of tasks within the project.

1. Adobe Workfront Documentation, "Add projects to a program": This guide details the process of associating a project with a program. The interface shown and the steps described involve selecting a single program for a project, and there is no mention of a prerequisite for tasks to exist. This supports the rejection of option C and the exclusivity principle of option B. (Source: Adobe Experience League, Workfront Documentation, "Add projects to a program," Section: "Add a project to a program from the project's page").

2. Adobe Workfront Documentation, "Create a project": The documentation for creating a project shows that "Portfolio" and "Program" are fields where a user selects a single value from a list. This user interface design enforces the constraint that a project can only belong to one of each at a time, directly supporting answer B. (Source: Adobe Experience League, Workfront Documentation, "Create a project," Section: "Create a project from scratch," Step 10 under "New Project" details).

3. Adobe Workfront Documentation, "Portfolios in Adobe Workfront": This overview describes a portfolio as a "collection of projects." The entire model is based on grouping unique projects. The documentation does not describe any mechanism for a single project to exist simultaneously in multiple portfolios, reinforcing the one-to-one relationship. (Source: Adobe Experience League, Workfront Documentation, "Portfolios in Adobe Workfront," Overview section).