Which one of the following is always true?

Select one:

a.The interquartile range is very unique in the sense that it is a measure of central tendency as well as a measure of dispersion.

b.The coefficient of variation is a measure of relative dispersion that expresses the standard deviation as a percentage of the mean, for any data on a ratio scale and an interval scale.

c.The coefficient of variation should only be used to compare positive data on an interval scale.

d.None of the suggested answers are correct

e.The coefficient of variation measures variability in a positively skewed data set relative to the size of the median.