A gas with $\large\frac {C_p}{C_v} = \gamma$ goes from an initial state of $(P_1,V_1,T_1)$ to a final state of $(P_2,V_2,T_2)$ through an adiabatic process. The work done by the gas is?

Question

$(A) \; \large\frac{nR (T_1-T_2)}{\gamma-1}$ $(B) \; \gamma \large\frac{(P_1V_1+P_2V_2) (T_1-T_2)}{\gamma-1}$ $(C) \; \gamma \large\frac{(P_1V_1+P_2V_2)}{\gamma-1}$ $(D) \; \large\frac{n\gamma R (T_1-T_2)}{\gamma-1}$