At STP, 2.00 moles of helium gas undergoes isothermal expansion so that the volume at point B is 3.2 times the volume at point A. The pressure drops to point C as heat is extracted at a constant volume. The gas goes back to its original state (A) through adiabatic compression. What are the pressures at points B and C? Assume helium gas behaves like an ideal gas.

• A. $P_{B}=0.31 \mathrm{~atm}, P_{C}=0.20 \mathrm{~atm}$
• B. $P_B=0.31\mathrm{~atm},P_C=0.14\mathrm{~atm}$
• C. $P_B=0.41\mathrm{~atm},P_C=0.20\mathrm{~atm}$
• D. $P_B=0.41\mathrm{~atm},P_C=0.14\mathrm{~atm}$