A Quantity of Ideal Gas Requires 800 KJ to Raise

A quantity of ideal gas requires 800 kJ to raise the temperature of the gas by 10.0 K when the gas is maintained at constant volume. The same quantity of gas requires 900 kJ to raise the temperature of the gas by 10.0 K when the gas is maintained at constant pressure. What is the adiabatic gas constant of this gas?

A) 0.889
B) 1.13
C) 1.22
D) 1.67
E) 1.40