A 2-M³ Weather Balloon Is Loosely Filled with Helium at 1

A 2-m³ weather balloon is loosely filled with helium at 1 atm (76 cm Hg) and at 27 $\degree$ C. At an elevation of 20,000 ft, the atmospheric pressure is down to 38 cm Hg and the helium has expanded, being under no constraint from the confining bag. If the temperature at this elevation is -48 $\degree$ C, the gas volume (in m³) is:

A) 3
B) 4
C) 2
D) 2.5
E) 5.3