Since the outlier is the least-fitting number in the data set, your outlier would be 3 since it is the farthest away from the rest of the numbers. You would be left with 14, 14, 16, 17, 19, 21, and 24. To find the range of the new data set you take the smallest value minus the largest value.
In conclusion, your answer is A) 10.
(24-14=10)