$17.$ A three$-$state pricing kernel has the following Arrow$-$Debreu $($AD$)$ prices: $$0\mathrm{.}20,$ $$0\mathrm{.}30$ and $$0\mathrm{.}45.$ What is the risk$-$free rate of return? $[$Hint: Think of the cash$-$flows that a risk$-$free investment would offer$]$

A$)$ Cannot be computed with the information given

B$)0\mathrm{.}95$

C$)5\%$

D$)5\mathrm{.}26\%$

E$)6\mathrm{.}32\%$