Two Moles of an Ideal Gas Have an Initial Kelvin

Multiple Choice

Two moles of an ideal gas have an initial Kelvin temperature Tᵢ and absolute pressure Pᵢ.The gas undergoes a reversible isothermal compression from an initial volume Vᵢ to a final volume 0.5Vᵢ.
-Which one of the following expressions represents the final pressure of the gas?

A) 0.5Pᵢ
B) Pᵢ/31.7
C) 2Pᵢ
D) 3.17Pᵢ
E) 4Pᵢ