First of all I should admit that I don't have teenagers. However I've seen variations on the above strategy be successfully used. My opinion is that teenagers need to learn to take responsibility for their actions. Part of taking responsibility is understanding that your choices carry real consequences. Family can help. But at some point you have to help yourself.

I guess there is a philosophy question here. To me it is very important that adults understand that while other people cannot choose what you'll do, you likewise cannot choose what they'll do.

As for what to do if she seriously decides on the last option, I assume from the description that she has a father. Let her live with him! (I have a sister who did exactly that at what I suspect was a similar age. I think it was good for her.) Or find some other relative for her to live with.

But the hope is that she won't decide on the last option. Very few teenagers are ready to do that. Instead the hope is that she'll accept tutoring.

Cheers,
Ben