The document discusses three graphs - A, B, and C - that could model having $5. Graph C, a downward sloping curve, was initially thought to be correct but the question asks why it is or isn't and why the other two aren't correct. The response explains that graph B, a linear positive slope, correctly represents the situation because as the amount purchased increases, the cost also increases, unlike graph C. Graph B is identified as the appropriate choice to model having $5.