A 9 by 4 centimeter rectangle expands in such a way that the 9–centimeter side is expanding at the rate of 5 centimeters per second and the proportions of the rectangle remain constant. At what rate is the area of the rectangle increasing when its dimensions are 36 by 16 centimeters? A.
120 cm2/s
B.
140 cm2/s
C.
160 cm2/s
D.
180 cm2/s