Answer:
A. the mode.
Step-by-step explanation:
Mean
Sum of all values divided by the number of values, so is affected by an outlier present in the data-set.
Standard deviation:
Square root of the sum of the differences squared between each value and the mean, divided by the sample size. As it's related to the mean, it is affected by an outlier.
Range:
Subtraction of the largest value of the data-set by the smallest value, and thus, is also affected by an outlier.
Mode
Value that appears the most often in the data-set, and thus, not affected by an outlier, which means that the correct answer is given by option A.
