Currently, you own a portfolio comprised of the following three securities$.$ How much of the riskiest security should

you sell and replace with risk$-$free securities if you want your portfolio beta to equal $90$ percent of the market beta?

Multiple Choice

$$7,023\mathrm{.}15$

$$7,811\mathrm{.}29$

$$8,666\mathrm{.}67$

$$7,753\mathrm{.}51$

$$8,318\mathrm{.}50$