I think that the 1st one is B, because if they can change the polices or beliefs, then they must have power, right? I'm not totally sure, tho.
The 2nd one is A, because, for example, a poster says "You will get stares from movie stars" or something like that, you probably will think, "I want movie stars to look like me!". Hence, the persuasion.
Hope this helped, sorry if I'm incorrect!
~Mshcmindy
