Answer:
Suppose that the mean score is M, and the range of scores is R.
The range is the difference between the largest score and the smallest score.
So, if the largest score is L, and the smallest score is S, we have:
R = L - S
Now, if the value of R increases, means that the difference between L and S also increases.
So having a large range usually is also a sign of having large variability.
Then:
a: Based on the information above, which class's scores have the most variability?
The class's scores with the most variability will be the class's scores with the largest range, in this case, the largest range of scores is for Class D.
b: Based on the information above, which class's scores have the least variability?
Now we need to look at the class with the least range of scores, in this case, the smallest one is the one for Class A.
