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) 70.02 to 81.98
b) 69.82 to 82.18
c) 70.06 to 81.94
d) 69.48 to 82.52