<p>One C will not kill you, please. I understand your frustration and worry, but it’s better to move on. Are you aiming for Berkeley and UCLA or Ivies/more caliber colleges? I have a friend who had multiple Cs that were, thankfully, balanced out by her As and Bs and got into UCLA. I was actually kind of surprised. Haha. I have another friend who received a single C like you in AP Calculus AB in 11th grade; he got into all the UCs, BU, Boston college, and NYU. How close were you to a B? Is it an AP class? Bargain with your teacher, somehow, if you can. How are your grades in other classes?</p>