Suppose the estimated quadratic model Yt = 500 + 20 t - t2 is the best-fitting trend of sales of XYZ Inc. using data for the past twenty years (t = 1, 2,.., 20).

Which statement is incorrect?
A. The trend was higher in year 10 than in year 20.
B. Latest year sales are no better than in year zero.
C. The turning point would be in period 10.
D. Sales are increasing by about 20 units per year.

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