One mole of a gas obeying the equation of state P(V-b) = RT is made to expand from a state with coordinates $$(P_1, V_1)$$ to a state with $$(P_2, V_2)$$ along a process that is depicted by a straight line on a P-V diagram. Then, the work done is given by

A

$$\frac{1}{2}(P_2 - P_1)(V_2 + V_1 + 2b)$$

B

$$\frac{1}{2}(P_1 + P_2)(V_2 - V_1)$$

C

$$\frac{1}{2}(P_2 - P_1)(V_2 - V_1)$$

D

$$\frac{1}{2}(P_1 + P_2)(V_2 - V_1 + 2b)$$