A school is interested in whether a personal appeal to parents will influence the money they give toward a scholarship. The average parent gives 26 dollars. One hundred randomly selected parents receive a hand written letter and a photo of a previous scholarship recipient. These parents subsequently give an average of 27.50 dollars, with a standard deviation of 40 cents. Test with an alpha of 0.01, using a two tailed test. What is the appropriate test statistic? Select one: none of these choices O a. O b. t = 3.75 O c. t = 37.5 O d. z = 3.75 O e. z = 37