If the balloon rises quickly, so that no heat transfer is possible, the temperature inside the balloon will drop as the gas expands. If a $4.0 \mathrm{~m}^{3}$ balloon is launched at a pressure of $100 \mathrm{kPa}$ and rapidly rises to a point where the pressure is $50 \mathrm{kPa}$, the volume of the balloon will be
A. Greater than $8.0 \mathrm{~m}^{3}$
B. $8.0 \mathrm{~m}^{3}$
C. Less than $8.0 \mathrm{~m}^{3}$