Why is the standard deviation preferable to the range as a measure of variation? select the correct answer below. a. the standard deviation is preferable to the range as a measure of variation because the standard deviation takes into account all of the observations, whereas the range considers only the largest and smallest ones. b. the standard deviation is preferable to the range as a measure of variation because the standard deviation is resistant to outliers, whereas the range is not. c. the standard deviation is preferable to the range as a measure of variation because it is optimal when the median is used as the center of measure. d. the standard deviation is preferable to the range as a measure of variation because the standard deviation is always smaller than the range?