In the given figure. $$PQRS$$ is a quadrilateral. If $$QR = 18 cm$$ and $$PS = 9 cm$$. then what is the area (in $$cm^2$$) of quadrilateral $$PQRS$$?

A

$$\frac{(64\surd3)}{3}$$

B

$$\frac{(177\surd3)}{2}$$

C

$$\frac{(135\surd3)}{2}$$

D

$$\frac{(98\surd3)}{3}$$