Suppose the average Math SAT score for all students taking the exam this year is 480 with standard deviation 100. Assume the distribution of scores is normal. A SRS of four students is selected and given special training to prepare for the Math SAT. The mean Math SAT score of these students is found to be 560, 80 points higher than the national average. We may correctly conclude
A. the results are neither statistically significant at level = 0.05 nor practically significant.
B. the results are not statistically significant at level = 0.05, but they are practically significant.
C. the results are statistically significant at level = 0.05, but they are not practically significant.