A Piece of Tin, Y = 12 Inches on a Side

Multiple Choice

A piece of tin, y = 12 inches on a side, is to have four equal squares cut from its corners, as in the illustration.If the edges are then to be folded up to make a box with a floor area of 16 square inches,
Find the depth of the box.

A) 9 in
B) 4 in
C) 8 in
D) 7 in
E) 11 in