If the standard deviation of the data : 7, 10, 13, 16, ... , 121 is $$\sigma$$ then the standard deviation of the data 50, 71, 92, .... 848 is

A

$$\sigma^{2} + 1$$

B

$$8\sigma$$

C

$$7\sigma^{2} + 1$$

D

$$7\sigma$$