For the following questions: You invest $$100$ in a risky asset with an expected rate of return of $15\%$ and a standard deviation of $15\%$ and a T$-$bill with a rate of return of $5\%($and a standard deviation of $0).$

What percentages of your money must be invested in the risky asset and the risk$-$free asset, respectively, to form a portfolio with an expected return of $13\%?$

$7.$ What percentages of your money must be invested in the risk$-$free asset and the risky asset, respectively, to form a portfolio with a standard deviation of $8\%?$

A$)67\%$ and $33\%$

B$)53\%$ and $47\%$

C$)27\%$ and $73\%$

D$)47\%$ and $53\%$

Just need to answer $7$th question. please do it carefully. I got the answer, but got it two answers.