The correct answer is D.14. The interquartile range is the difference between the Upper Quartile and the Lower Quartile of a data set.
By arranging the numbers in the stem and leaf plot from lowest to highest value, you get an even set of data (31,33,35,41,43,46,48,49,49,50). By dividing the set into two, you get a lower half of your data (31,33,35,41,43) and an upper half (46,48,49,49,50). The lower quartile is the median or the midpoint of the lower half of your data while upper quartile is for the upper half. The lower quartiles is 35 and upper quartile is 49. The difference between the two is 14.
