Solve the Problem $\$ 45$ Each Month to Spend on Books and CDs

Multiple Choice

Solve the problem.
-Alison sets aside $\$ 45$ each month to spend on books and CDs. If she spends c dollars on CDs in a given month she may spend $b$ dollars on books where $c+b=45$ . Graph the equation and use the graph to estimate the amount Alison may spend on books in March if she spends $\$ 32$ on CDs.

A) $\$ 77$
B) $\$ 24$
C) $\$ 20$
D) $\$ 13$