Which of the following statements is most correct?

a. Because a business firm can be viewed as a portfolio of assets, it is important that the firm maintain a diversified portfolio of investments in order to reduce firm diversifiable risk.

b. Firms are rewarded for choosing and implementing from among a diversifiable collection of projects through higher stock values.

c. Firms generally are not rewarded for choosing and implementing from among a diversifiable collection of projects through higher stock prices.

d. Two of the above are true.