An Open Box Is to Be Made from a Square

An open box is to be made from a square piece of cardboard, 24 inches by 24 inches, by removing a small square from each corner and folding up the flaps to form the sides. What are the dimensions of the box of greatest volume that can be constructed in this way?

A) 8 inches long by 8 inches wide by 4 inches deep
B) 12 inches long by 12 inches wide by 4 inches deep
C) 4 inches long by 4 inches wide by 16 inches deep
D) 16 inches long by 16 inches wide by 4 inches deep