A researcher randomly assigned boys and girls to each of two groups. One group watched a violent television program while the other group watched a nonviolent program. The children were then observed during a period of free play, and the incidence of aggressive behavior was recorded for each group. What is the dependent variable in this study?a) Sex of the childrenb) Duration of free playc) Type of television program viewedd) Level of televised violencee) Incidence of aggressive behavior