A poster is to contain 600 cm2 of printed text. The margins are to be 2 cm on each side and 4 cm at the top and bottom. What width w of the printed region (to the nearest tenth of a centimeter) minimizes the total area of the poster?
a) 20.0 cm
b) 17.3 cm
c) 24.5 cm
d) 12.2 cm