It would be more effective to persuade the teenager smokers to give up smoking ifA．the sch

It would be more effective to persuade the teenager smokers to give up smoking if

A．the schools showed more pictures of smokers' lungs to the teenager smokers

B．the cigarette vending machines could be completely eliminated

C．the federal excise tax on cigarettes would be further increased

D．the teenager smokers would be convinced by their own fellow pupils