A student took a chemistry exam where the exam scores were mound-shaped with a mean score of 90 and a standard deviation of 64. She also took a statistics exam where the scores were mound-shaped, the mean score was 70 and the standard deviation was 16. If the student's grades were 102 on the chemistry exam and 77 on the statistics exam, then:
a. the student did relatively better on the chemistry exam than on the statistics exam, compared to the other students in each class
b. it is impossible to say which of the student's exam scores indicates the better performance
c. the student did relatively better on the statistics exam than on the chemistry exam, compared to the other students in the two classes
d. the student's scores on both exams are comparable, when accounting for the scores of the other students in the two classes
e. the student did relatively the same on both exams