What does global research reveal about the peak age for the emergence of sex differences in unipolar depression?

A. Sex differences in depression emerge at age seventeen and peak in young adulthood.
B. Sex differences in depression emerge at age twelve and peak during middle adolescence.
C. There are relatively minor sex differences in unipolar depression between adolescent boys and girls.
D. Compared to adolescent girls, adolescent boys tend to have higher rates of unipolar depression.

Answer: B