Which operative indicator must be checked for WBS that can have planned costs entered?

The correct answer is the Planning Element, as it determines whether costs can be planned and entered for a Work Breakdown Structure (WBS) element in project management systems like GFEBS. The Planning Element serves as a crucial link in the project planning process; it ensures that costs associated with a project are properly allocated and can be tracked.

With a valid Planning Element in place, users can proceed to input planned costs, which are essential for budget management and financial forecasting. These costs can include estimates for labor, materials, and other resources that will be required to complete the project successfully.

The other options, while related to project management and cost tracking, do not specifically indicate the capability of entering planned costs. For instance, Project Assignment Element relates to organizational responsibility, Billing Element pertains to invoicing processes, and Account Assignment Element is focused on financial postings rather than specifically about planning and entering costs. Hence, the Planning Element is essential for enabling cost planning in WBS.