Answer:
Standard deviation
Explanation:
You use the standard deviation to determine how far the particular mark is further away from the mean. It shows how that particular data point agrees with the mean.
A is wrong
The mean is the average of the data. It does not tell you the information needed in this question.
B is wrong
The mode is just the highest in frequency. It does not say anything about agreeing with the mean
C is wrong
This is wrong and it refers to the middle number in the data set