If not enough resources are available for a project, to maintain the same project scope and budget, the project team should

delay some activities until the resource is available

Explanation:

Continue to start the project without complete resources to use, will eventually lead to delay in other parts of a project. For example, if resources for part D to J are not available, and the project is sequential, it will surely affect the progress of part A to C, and at the same time, the project will not able to jump to point K.

Hence, to avoid the scope of the project to change, which will in turn affect the budget if one wants to surge ahead, it is better to "delay some activities until the resource is available."