A Private Shipping Company Will Accept a Box for Domestic $90 \mathrm{in}$

Multiple Choice

A private shipping company will accept a box for domestic shipment only if the sum of its length and girth (distance around) does not exceed $90 \mathrm{in}$ . Suppose you want to mail a box with square sides so that its dimensions are $\mathrm{h}$ by $\mathrm{h}$ by $\mathrm{w}$ and it's girth is $2 \mathrm{~h}+2 \mathrm{w}$ . What dimensions will give the box its largest volume?

A) 20 in. $x 20$ in. $x 15$ in.
B) 15 in. $x 15$ in. $x 30$ in.
C) 30 in. $x 15$ in. $x 30$ in.
D) 15 in. $x 15$ in. $x 75$ in.