For every 3^{\circ} rise in itemperature, the volume of a certain gas expands by 4 cubic centimeters. If the volume of the gas is 24 cubic centimeters when the itemperature is 32^{\circ}, what was the volume of the gas in cubic centimeters when the itemperature was 20^{\circ} ?
Answer Choices
A. 8
B. 12
C. 15
D. 16
E. 40