Find the Standard Deviation of the Data Summarized in the Given

Multiple Choice

Find the standard deviation of the data summarized in the given frequency distribution.
-The test scores of 40 students are summarized in the frequency distribution below. Find the standard deviation. $$\begin{array}{l}\text { Score Students }\\\begin{array} { r r } 50 - 59 & 5 \\60 - 69 & 7 \\70 - 79 & 9 \\80 - 89 & 10 \\90 - 99 & 9\end{array}\end{array}$$

A) 12.7
B) 13.4
C) 14.1
D) 12.1