Using Sales Force Estimates for Forecasting Has the Advantage That

Using sales force estimates for forecasting has the advantage that

A) confusion between customer "wants" (wish list) and customer "needs" (necessary purchases) is eliminated.
B) statistical estimates of seasonal factors are more precise than any other approach.
C) forecasts of individual sale force members can be easily combined to get regional or national sales totals.
D) no biases exist in the forecasts.