Final answer:
All of the above: Sales forecast, production capacity, and inventory levels are inputs to aggregate planning.
Step-by-step explanation:
The correct answer is All of the above. All three options—sales forecast, production capacity, and inventory levels—are inputs to aggregate planning.
Sales forecast provides information on the expected demand for products, which helps in determining the level of production needed. Production capacity indicates the maximum quantity of goods that can be produced within a given timeframe, allowing for adjustments in the production plan. Inventory levels help in assessing the availability of finished goods and the need for production adjustments to meet demand.