Which of the following completes the project triangle along with scope and time?

The correct answer is cost, which is a fundamental component that, along with scope and time, forms the project management triangle, also known as the "triple constraint." This triangle represents the interdependent nature of these three key aspects of project management.

When managing a project, any change to one of these elements will inevitably affect the other two. For instance, if you want to increase the scope of a project, you may need to either extend the time to complete it or increase the cost to accommodate additional resources or manpower to meet the expanded requirements. Conversely, if there's a need to shorten the time frame, this may lead to increased costs, such as hiring additional staff or paying for expedited shipping on materials.

Cost is directly tied to the resources needed to complete the project, such as human labor, equipment, and materials. Effective project management ensures that a balanced approach is taken to manage these three elements, optimizing them to achieve project success while staying within financial and operational constraints. By understanding how cost interacts with scope and time, a project manager can make informed decisions to keep the project on track and within budget.