Use the Data Given to Calculate the Value of DG ^$\circ$

Use the data given to calculate the value of DG ^$\circ$ _rxn at 25 ^$\circ$ C for the reaction given below. DG ^$\circ$ _f for CO(g) is -137.16 kJ/mol.

A) -274.32 kJ
B) -137.16 kJ
C) -68.58 kJ
D) +137.16 kJ
E) +274.32 kJ