What is the standard deviation of returns of this stock?

a$.3\mathrm{.}42\%$

b$.3\mathrm{.}72\%$

c$.3\mathrm{.}80\%$

d$.4\mathrm{.}13\%$

e$.4\mathrm{.}97\%$

You have observed the historical monthly returns of asset $A$ :

Month

Returns $\%$

$1$

$8$

$2$

$2$

$3$

$-2$

$4$

$0$

$5$

$0\mathrm{.}5$

$2.$ What is the arithmetic mean return of this stock?

a$.1\mathrm{.}70\%$

b$.1\mathrm{.}92\%$

c$.2\mathrm{.}19\%$

d$.2\mathrm{.}59\%$

e$.3\mathrm{.}14\%$