Among the options provided, the risk factor that you can control is related to your friends smoking. While you cannot control the fact that your friends have started smoking, you can control your own choice to smoke or not, and you can also make decisions about the friends you choose to spend time with.
The other risk factors, such as the incidence of high blood pressure in your ethnic group, the leading cause of death for teens (unintentional accidents), and a family history of heart disease, are not controllable factors.