A researcher believes that the ankle circumference for adult males in Europe can be considered to have a normal distribution with a mean of 24 cm. If his belief is correct, which of the following ranges of ankle sizes will have the largest proportion of members of this population?
1) 15 to 21 cm
2) 21 to 27 cm
3) 27 to 33 cm
4) It is impossible to tell without the standard deviation.