\(\begin{array}{c|c}
Class Interval & 3 - 5 & 6 - 8 & 9 - 11 \\ \hline Frequency & 2 & 2 & 2 \end{array}\). Find the standard deviation of the above distribution.

• A.√5
• B.√6
• C.√7
• D.√2
• E.