The main differences between debt and equity are the following:

• Debt is not an ownership interest in the firm. Creditors do not generally have voting power.

• The corporation’s payment of interest on debt is considered a cost of doing business and is fully tax deductible. Dividends paid to stockholders are not tax deductible.

• Unpaid debt is a liability of the firm. If it is not paid, the creditors can legally claim the assets of the firm. This action can result in liquidation or reorganization, two of the possible consequences of bankruptcy. Thus, one of the costs of issuing debt is the possibility of financial failure. This possibility does not arise when equity is issued. 

Therefore, the correct option is A.