Analyze the cost of capital situations of the following company cases, and answer the specific questions that finance professionals need to address.

Consider the case of Turnbull Co$.$

Turnbull Co$.$ has a target capital structure of $58\%$ debt, $6\%$ preferred stock, and $36\%$ common equity. It has a before$-$tax cost of debt of $8\mathrm{.}2\%,$ and its cost of preferred stock is $9\mathrm{.}3\%.$

If Turnbull can raise all of its equity capital from retained earnings, its cost of common equity will be $12\mathrm{.}4\%.$ However, if it is necessary to raise new common equity, it will carry a cost of $14\mathrm{.}2\%.$

If its current tax rate is $25\%,$ how much higher will Turnbull's weighted average cost of capital $($WACC$)$ be if it has to raise additional common equity capital by issuing new common stock instead of raising the funds through retained earnings? $($Note: Round your intermediate calculations to two decinal places.$)$

$0\mathrm{.}81\%$

$0\mathrm{.}85\%$

$0\mathrm{.}55\%$

$0\mathrm{.}65\%$