A researcher randomly assigns 50 children to play either violent video games or nonviolent video games. After 90 minutes of play, has the children interact and measures the level of aggression displayed by each child. For this study, what is the dependent variable?

a. whether the child played violent or nonviolent video games

b. how aggressive the child was before the violent video game

c. the level of aggression displayed by the children

d. the children in the study