Should my mom spend $900 for a class? retaking a "C": Help concerned son!

<p>My daughter had a C in elementary functions. She was frustrated because after helping other classmates with the concepts, she totally blew the final! Her other math grades were all Bs.
She was admitted to JHU early decision.
I think that she made a good tactical decision when she asked a math teacher (not the one who gave the C) to write one of her recommendations. I am not sure what this teacher wrote, but the teacher may have written about how she had excellent conceptual understanding of math.</p>