Expected Return Standard Deviation

Stock X

$8\%$

$0\mathrm{.}12$

Stock $Y$

$6\%$

$0\mathrm{.}09$

Correlation $(x,Y)=0\mathrm{.}5$

You invest $$1000$ is Stock $x$ and $$4000$ in Stock $Y.$ What is your portfolio standard deviation of returns?

$8\mathrm{.}653\%$

$7\mathrm{.}488\%$

$7\mathrm{.}550\%$

none of the choices