Which one of the following statements concerning preferred stock is correct? Select one:

a. Preferred shareholders may be granted voting rights if preferred dividend payments remain unpaid.

b. Unpaid preferred dividends are a liability of the firm whether or not they have been declared.

c. All unpaid dividends on both cumulative and non-cumulative preferred stock must be paid before any common stock dividends are declared.

d. Preferred dividends will be paid quarterly only when the firm has current net income that exceeds the amount of the quarterly dividend.

e. Any unpaid preferred dividends will accrue interest at a rate equal to the dividend rate.