In a Study of 7- to 10-Year-Old Children in China

In a study of 7- to 10-year-old children in China, Colombia, Italy, Jordan, Kenya, the Philippines, Sweden, Thailand, and the United States, which asked the kids themselves to report on their use of both kinds of aggression, Lansford et al. (2012) found that in all nine countries

A) boys were more physically aggressive than girls.
B) boys were more likely than girls to use indirect, relational aggression.
C) there was a relatively small effect size for physical aggression in favor of boys.
D) there was a significantly large effect size for relational aggression in favor of boys.