The test scores of the students in four classes are summarized below. Answer the questions about them.

Class A: The mean score is117

and the range of scores is39

.

Class B: The mean score is115

and the range of scores is38

.

Class C: The mean score is109

and the range of scores is47

.

Class D: The mean score is108

and the range of scores is45

.

(a)Based on the information above, which class has the lowest scores on average?

Class A

Class B

Class C

Class D

(b)Based on the information above, which class's scores have the least variability?

Class A

Class B

Class C

Class D