A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. Final examination scores from a random sample of students enrolled today and from a random sample of students enrolled five years ago were selected. You are given the following information.

	Today	Five Years Ago
x	81	89
2	78	367.5
n	52	49

The 95% confidence interval for the difference between the two population means (Today - Five Years Ago) is _____.

a. -13.88 to -2.12

b. -25.64 to 9.64

c. -3.29 to 3.29

d. -12.93 to 12.23