Returns for the Shields Company Over the Last Three Years $\begin{array}{cr}\text { Year } & \text { Return } \\\hline 2009 & 21.50 \% \\2008 & -12.50 \% \\2007 & 24.20 \%\end{array}$

Multiple Choice

Returns for the Shields Company over the last three years are shown below.What's the standard deviation of Shields' returns? (Hint: This is a sample,not a complete population,so the sample standard deviation formula should be used.) $\begin{array}{cr}\text { Year } & \text { Return } \\\hline 2009 & 21.50 \% \\2008 & -12.50 \% \\2007 & 24.20 \%\end{array}$

A) 19.94%
B) 20.45%
C) 20.97%
D) 21.49%