If $$r = 15\left(\sin \theta + \cos \theta \right)$$ and $$s = 16(\sin \theta - \cos \theta)$$ , then the value of $$\frac{r^{2}}{15^{2}} + \frac{s^{2}}{16^{2}}$$ _________.

A

8

B

6

C

4

D

2