The bottom-up method for forecasting sales relies on the ability of complex statistical models to predict individual unit or regional sales figures, which are added together and reported to senior managers B relies on the ability of senior managers to determine sales objectives for their company's product and inform personnel about targets for each business unit relies on the ability of sales personnel to correctly apply statistical models in order to obtain firm-wide objectives for increased sales D relies on the ability of sales personnel to assess future demand, usually without the aid of statistical models