An ideal gas in a thermally insulated vessel at internal pressure = $$P_1$$, volume = $$V_1$$ and absolute temperature = $$T_1$$ expands irreversibly against zero external pressure, as shown in the diagram. The final internal pressure, volume and absolute temperature of the gas are $$P_2, V_2$$ and $$T_2$$, respectively. For this expansion,

A

$$q = 0$$

B

$$T_2 = T_1$$

C

$$P_2 V_2 = P_1 V_1$$

D

$$P_2 V_2^\gamma= P_1 V_1^\gamma$$