A Firm's Debt to Equity Ratio Varies at Times Because

A firm's debt to equity ratio varies at times because:

A) a firm will want to sell common stock when prices are low and bond when interest rates are high.
B) a firm will want to take advantage of timing its fund raising in order to minimize costs over the long run.
C) the market allows extensive leeway in the debt to equity ratio before penalizing the firm with a higher cost of capital.
D) of the cyclical nature of the industry in which the firm operates.