The US Postal Service (USPS) Will Accept Only Packages with Length

Multiple Choice

The US Postal Service (USPS) will accept only packages with length plus girth no more than 120 inches. (See the figure.)
What are the dimensions of the largest volume package the USPS will accept

A) $24 \times 24 \times 24$ inches
B) $24 \times 24 \times 48$ inches
C) $20 \times 20 \times 40$ inches
D) $24 \times 48 \times 48$ inches
E) $40 \times 40 \times 40$ inches