Kara should use Box C. The correct answer is OC) Box C.
To determine which shipping box Kara should use, we need to compare the volume of her gift box with the volumes of the available shipping boxes.
The volume of Kara's cube-shaped gift box is given by the formula:
Volume of cube=

For Kara's gift box:
Volume of Kara’s box=

Now, let's compare this with the volumes of the available shipping boxes:
Volume of Box A=

Volume of Box B=

Volume of Box C=

Volume of Box D=

Kara should choose the shipping box that is large enough to accommodate her gift. In this case, Box C has a volume of 343 in³, which is more than enough to fit Kara's gift (216 in³). Therefore, Kara should use Box C. The correct answer is OC) Box C.