Name the measure of variability that best represents this set of data:
3, 18, 2, 0, 1, 0, 2, 1

The correct answer is: IQR

Step 1 of 2:
Given the dataset, 3, 18, 2, 0, 1, 0, 2, 1
The data that is different from other numbers in the given set is 18.
So, there is an outlier present in the dataset and it is 18.
Step 2 of 2:
Now, the IQR describes the middle 50% of values when ordered from lowest to highest. To find the interquartile range (IQR), ​first, find the median (middle value) of the lower and upper half of the data. These values are quartile 1 (Q1) and quartile 3 (Q3). The IQR is the difference between Q3 and Q1.  
Hence, use the IQR when the median is the appropriate measure of center.
Final Answer:
The right choice is-- a. IQR