How bad do I have to do to get rejected after acceptance?

<p>I was around a B+ student my highschool year but this senior year I have around a C in AP physics and a C in AP calculus.</p>

<p>Out of the 5 schools that have sent a message back, 4 accepted. How bad do I have to be doing for them to change their decision and reject me? And how long will it be until they send me a message saying they want to reject me? </p>

<p>woops wrong section</p>