Bomeara,
Hello and welcome to PC!
You’re daughter is a young woman and I’d talk to her as such. Make a compromise, she can remain in the school she’s comfortable in, but she’s going to put some effort into her school work.
The books come home, and you check her homework. If she fails to turn it in on time (most schools here you can check these things online daily) then she loses phone privileges etc.
I wouldn’t push, I would encourage. Small steps, bring the C’s up to B’s and try to bring the B’s up to A’s. Tell her that you know she’s intelligent and you expect her to do her best, no more, no less.
You’re the parent, don’t argue! Tell her what you expect of her and why. No negotiation when it comes to homework. If she doesn’t put any effort into it, I’d nip the social stuff. Dances and things are coming up, she’s going to want to go.
Good luck!