Stock $x$ has a standard deviation of return of $25$ percent. Stock $Y$ has a standard deviation of return of $5$ percent. The correlation coefficient between the two stocks is $0\mathrm{.}5.$ If you invest $60$ percent of your funds in Stock $x$ and $40$ percent in Stock $Y,$ what is the standard deviation of your portfolio?

Multiple Choice

$14\mathrm{.}2$ percent

$24\mathrm{.}9$ percent

$16\mathrm{.}1$ percent

$18\mathrm{.}7$ percent