Which of the Following Is Most Correct

Which of the following is most correct?

A) When the return on capital employed (ROCE) is less than the before tax cost of debt, a company can increase its ROE by trading out equity and into debt.
B) When the return on capital employed (ROCE) is more than the before tax cost of debt, a company can increase its ROE by trading out equity and into debt.
C) When the return on capital employed (ROCE) is less than the after tax cost of debt, a company can increase its ROE by trading out equity and into debt.
D) When the return on capital employed (ROCE) is more than the after tax cost of debt, a company can increase its ROE by trading out equity and into debt.