Initial pressure and volume of a monoatomic ideal gas are $$P$$ and $$V$$. The change in internal energy of this gas in adiabatic expansion to volume $$V_{final} = 27V$$ is __________ J.

A

$$-2PV(3\sqrt{3} - 1)$$

B

$$\frac{4}{3}PV$$

C

$$-\frac{4}{3}PV$$

D

$$\frac{3}{4}PV$$