Which of the following calculates a 10% commission on the values in the Sales field and then stores the results in the Commission field?
a. SELECT Year, Sales, Commission = Sales * 0.1 FROM dbo.TrentSales
b. SELECT Year, Sales, AS Commission = Sales * 0.1 FROM dbo.TrentSales
c. SELECT Year, Sales, Sales * 0.1 = Commission FROM dbo.TrentSales
d. SELECT Year, Sales, Sales * 0.1 AS Commission FROM dbo.TrentSales