The expected return of a portfolio is $8\mathrm{.}9\%,$ and the risk$-$free rate is $3\mathrm{.}5\%.$ If the portfolio standard deviation is $12\%,$ what is the reward$-$to$-$variability ratio of the portolio?Group of answer choices$0\mathrm{.}451\mathrm{.}350\mathrm{.}000\mathrm{.}74$