One of the Main Problems in Concluding Anything About the Role

One of the main problems in concluding anything about the role of gender in verbal, quantitative, and spatial abilities is

A) these abilities change so much over the developmental span, and boys and girls experience many fluctuations in their performance.
B) that the role of hormones has not been studied.
C) meta-analytic studies indicate that there are no gender differences in any of these areas.
D) each of these areas has been defined using so many different types of tasks that underlying ability is difficult to determine.