A random sample of 25 statistics examinations was taken. The average score in the sample was 76 with a variance of 144. Assuming the scores are normally distributed, the 99% confidence interval for the population average examination score is:

a. 69.48 to 82.52

b. 70.06 to 81.94

c. 69.29 to 82.71

d. 70.02 to 81.98