An unlevered firm operates in perfect capital markets except that there are both corporate and personal taxes. The corporate tax rate is 21%, the personal tax rate on Income from stock is 15%, and the personal tax rate on interest income from debt is 37%. If the firm borrows $10 million at 4% interest and uses the proceeds to retire stock, the value of the firm O increase by about $660,000 not change at all O decrease by about 6.6% O decrease by about $660,000