Carissa has $15 to spend on folders and notebooks. Folders cost $1.25 each and notebooks cost $2.50 each. How can we graph Carissa's budget constraint?
A) By moving the endpoints of the line segment in the graph
B) By calculating the total cost of folders and notebooks
C) By determining the number of folders and notebooks Carissa can buy
D) By analyzing the relationship between Carissa's budget and the cost of folders and notebooks.