Returns for the Alcoff Company Over the Last 3 Years $$\begin{array} { r r } \frac { \text { Year } } { 2010 } & \frac { \text { Return} } { 21.00 \% } \\2009 & - 12.50 \% \\2008 & 25.00 \%\end{array}$$

Returns for the Alcoff Company over the last 3 years are shown below.What's the standard deviation of the firm's returns? (Hint: This is a sample,not a complete population,so the sample standard deviation formula should be used.) $$\begin{array} { r r } \frac { \text { Year } } { 2010 } & \frac { \text { Return} } { 21.00 \% } \\2009 & - 12.50 \% \\2008 & 25.00 \%\end{array}$$

A) 20.08%
B) 20.59%
C) 21.11%
D) 21.64%
E) 22.18%