A portfolio analyst has been asked to allocate investment funds among three different stocks. The relevant data for the stocks is shown in the following table. If the goal is to minimize risk while maintaining a return of at least $18\%,$ find the proper allocation of the funds to each stock.

Stock Return $($R$)$ Risk $($Standard Deviation to S$)$ Pair of Stocks Joint Risk $($Covariance$)$

A $25\%21\%$ A to B $0\mathrm{.}05$

B $19\%16\%$ A to C $0\mathrm{.}075$

C $8\%14\%$ B to C $0\mathrm{.}05$

What is the risk $($standard deviation$)$ of the optimal portfolio?

Multiple Choice

$11\mathrm{.}4\%$

$18\mathrm{.}0\%$

$9\mathrm{.}1\%$

$12\mathrm{.}2\%$

$15\mathrm{.}0\%$