The standard deviation of the tap water data is 1.086. The standard deviation of the salt water data is 1.107. Which explains why the standard deviation is the best measure of variability to use to compare the data?

The two distributions are each nearly symmetric.
The distributions do not overlap on the same range of temperatures.
The distribution of salt water boiling temperatures is left-skewed.
The distribution of tap water boiling temperatures is right-skewed.