Compute the Standard Deviation of the Expected Return Given These

Multiple Choice

Compute the standard deviation of the expected return given these three economic states, their likelihoods, and the potential returns:
$$\begin{array}{l}\begin{array} { c c r } \text { Eccrorric State }&\text { Probability } & \text { Return } \\\text { fast growth }&0.1 & 50 \% \\\text {slow growth }&0.6 & 8\% \\\text { recession }&0.3 & - 10\%\end{array}\end{array}$$

A) 6.8 percent
B) 16.5 percent
C) 21.5 percent
D) 46.4 percent