Which One of the Following Statements About Aggregate Planning Is

Which one of the following statements about aggregate planning is best?

A) A production plan generally focuses on production rates and inventory holdings, whereas a staffing plan focuses on staffing and other labor-related factors.
B) Capacity alternatives are actions that adjust demand patterns.
C) Operations and marketing are the only two functional areas that supply inputs for developing production and staffing plans.
D) A level strategy stabilizes inventory levels by adjusting production rates or staff levels to match demand levels over the planning horizon.