Which of the following statements is not correct?

a. The price of an American call on a non-dividend paying stock cannot be less than the difference between the current stock price and the present value of the exercise price.

b. The put-call parity holds for dividend-paying stocks.

c. The shareholders' position can be considered as a long call on the value of the firm.

d. The creditors' position can be considered as the face amount of debt and a long put on the value of the firm.