The interest tax shield has no value for a firm when the:

I. the tax rate is equal to zero.

II. the debt-equity ratio is exactly equal to 1.

III. the firm is unlevered.

IV. a firm elects an all-equity capital structure.

A.I only

B	I, III and IV only

C	I, II, III and IV

D	II and IV only

E	III and IV only