I was in that situation.
I'm getting a C in biology right now. I have thought about dropping it for a while.
I am sticking with it is because I need to be full time student for insurance coverage.
I remember making a topic a while back asking about C's, and I've read that one or two will not hurt you. What if you retake it and still don't get the grade you want?
I figure I will apply with that grade, and if I get in then that's great, but if I don't get in I can retake it during the year I would be improving my application.
I am focusing on doing well in future, more advanced classes.