Which of the following statements is not true regarding "convertible preferred" shares?

A) They allow the owner to "convert" the shares to common shares at a pre-set price for a stated period of time

B) The price of preferred shares is set at a premium to their conversion value to discourage early conversion by the owner

C) The premium for preferred shares is usually offset by the higher yield compared the common shares of the same company

D) The market price for a convertible preferred is fixed and will not change over time