If a data consisting of 25 observations $$\sum_{i=1}^{25}(x_{i} + 9)^{2} = 175$$ and $$\sum_{i=1}^{25}(x_{i}+9) =\frac{75}{2}$$, then the standard deviation of data is

A

$$\frac{9}{2}$$

B

$$\frac{19}{4}$$

C

$$\frac{\sqrt{19}}{2}$$

D

$$\frac{3}{\sqrt{2}}$$