How much is added to a firm's weighted$-$average cost of capital for $45\%$ debt financing with a required rate of return of $10\%$ and a tax rate of $35\%?$

A$)$: $1\mathrm{.}29\%$

B$)$: $2\mathrm{.}93\%$

C$)$: $3\mathrm{.}50\%$

D$)$: $4\mathrm{.}50\%$