Do colleges look down on C+ in Math if all other math grades are good?

I am applying to Bryn Mawr, and my only extremely bad grade on my entire transcript is the C+ in Pre-calculus (the rest of my application is actually really solid). In years past and my current senior year, I have only gotten A/B+s. This grade drop was only because of my transfer to my third high school which is a difficult college prep academy. Of course it isn’t a D or C- but it is still really bad. How bad will this make me look? Will college reps look down on me even though it’s my only bad math grade?

If you can clearly tell them, why your grade dropped then they should be able to understand it. If you don’t explain it then it will make you look bad.

If the trend is upward then it’s not so bad.