The firm has a net income of $$2\mathrm{.}3$ million. The firm's capital structure consists of Equity of $$15$ million and debt of $$10$ million. The firm pays $60\%$ of its earnings as dividends. The sustainable growth rate of the firm is:

$6\mathrm{.}53\%$

$3\mathrm{.}68\%$

$9\mathrm{.}20\%$

$5\mathrm{.}52\%$