Which chart is best suited for illustrating the relationship between phases of a project?

The Gantt Chart is particularly effective for illustrating the relationship between phases of a project because it provides a visual representation of the timeline for each phase, showing how they overlap and relate to one another. It displays tasks along a horizontal timeline, allowing viewers to easily see the start and end dates of each phase, their duration, and the dependencies between tasks.

This type of chart not only helps in scheduling and tracking project progress but also facilitates communication among team members and stakeholders about the project's status. The clear visual layout makes it easy to identify which phases are occurring simultaneously and what dependencies exist, making it an ideal tool for project management overall.

In contrast, pie charts are most effective for displaying proportions within a whole, line graphs show trends over time but do not detail phases or dependencies, and bar graphs compare quantities but lack the context of timing and relationships that Gantt charts provide. Thus, the Gantt Chart stands out as the most appropriate choice for this context.