need asap. finance major please answer all questions.

Facebook, Inc. has no debt. By issuingdebt, Facebook can generate a very large tax shield potentially worth nearly $2 billion. GivenFacebook's success, one would be hard pressed to argue thatFacebook's management arenave and unaware of this huge potential to create value. A more likely explanation is that issuing debt would entail other costs. Which of the following costs of debt is unlikely to explainFacebook's policy?

(Select the best choicebelow.)

A. Asset substitution

B. Cash flow volatility

C. Cash flow risk

D. Human capital risk