Final answer:
The correct answer is cross-project link, which means establishing a connection between tasks in different projects where one task is contingent upon the other, known as an external dependency in project management.
Step-by-step explanation:
You can create a cross-project link between projects if the completion of a task in one project has an effect on a task in another project. This concept is often referred to as an external dependency, where the start or finish of a particular task is dependent on the start or completion of another task outside of the current project's scope. Understanding and managing such dependencies is a key aspect of project management as they can significantly impact the project schedule and resource allocation.