The formula to calculate the volume of a prism is given as
[tex]V=\text{Base Area }\times Height[/tex]The volume is given as 45 and the height is 9.
Hence, we can get the base area as
[tex]\begin{gathered} A=\frac{V}{h} \\ A=\frac{45}{9} \\ A=5 \end{gathered}[/tex]Therefore, the area of the base is 5 ft².
The correct option is OPTION B.