From a thin piece of cardboard 30in by 30in, square corners are cut out so that sides can be folded up to make a box. What dimensions will yield a maximum volume? What is the maximum volume? Round to the nearest tenth, if necessary.

A) 20in x 20in x 5 in; 2000iin^3
B) 15in x 15in x 7.5in; 1687.5 in^3
C) 20in x 20in x 10in; 4000in^3
D) 10in x 10 in x 10in; 1000in^3