Final answer:
To generate a load-based schedule, one must select a predefined forecast, which is a projection of future workload and resources. A predefined schedule cannot adjust to fluctuating demands and is not suitable for load-based scheduling.
Step-by-step explanation:
To generate a load-based schedule, one must select a predefined forecast. Load-based scheduling involves estimating the amount of work, or load, involved and allocating resources accordingly. It's a method commonly used in project management and operations to ensure that workload is evenly distributed according to the forecasted demand. Choosing a magic wand or a rabbit would not be practical in this context. A predefined schedule is a fixed plan that does not change based on workload, and therefore is not suitable for load-based scheduling which requires adaptation to fluctuating loads. Hence, the correct answer is a predefined forecast which is a projection of future workload based on historical data, trends, and analyses.