Your friend cassidy is addicted to smoking; she has tried to quit on her own but always starts up again. she doesn't want her parents to know that she smokes, but she asks you to her quit. what is the best thing for you to do to cassidy?

call cassidy's parents anonymously and tell them the truth; hopefully they can make her quit
go with cassidy to talk with a trusted adult to find resources to her quit
tell cassidy you won't her; just because you are friends doesn't make this your problem
threaten to stop hanging out with cassidy if she ever smokes a cigarette again