North Around, Incorporated, stock is expected to return $22$ percent in a boom, $13$ percent in a normal economy, and $-15$ percent in a recession. The probabilities of a boom, normal economy, and a recession are $8$ percent, $90$ percent, and $2$ percent, respectively. What is the standard deviation of the returns on this stock? A$.4\mathrm{.}53\%0.$B$.18\mathrm{.}94\%$ C$.18\mathrm{.}79\%$ D$.10\mathrm{.}56\%$E$.4\mathrm{.}70\%$