Which of the following comparisons of the Capital Asset Pricing Model (CAPM) and the Arbitrage Pricing Model (APT) is (are) true?

- While CAPM requires a number of estimates, the APT factors and their values are known with certainty

- CAPM is based on the theory that an assets returns should compensate the investor for the risk of the investment. Risk is not factored into the APT

- CAPM bases the expected return on an asset on one "factor" - the market portfolio; the APT bases the expected return on a number of economic factors

- All of the are true