Polly Wants to Determine If Exposure to Violent Video Games

Polly wants to determine if exposure to violent video games leads to affinity of video game characters. To test this hypothesis, Polly has one group play a violent video game and one group play a nonviolent video game. Polly then has the participants fill out a mental measure
Examining affinity of video game characters. In essence, what is Polly trying to determine in this study?

A) time order
B) independent variable manipulation
C) stability of the dependent variable
D) possible intervening variables