Ken Wallace is interested in testing whether the average price to earnings (P/E) of firms in the retail industry is 25. Using a t - distributed test statistic and a 5% level of significance, the critical values for a sample of 40 firms is/are:()
A. -1.685 and 1.685.
B. -1.96 and 1.96.
C. -2.023 and 2.023.