what's the answer of following and why?

Suppose the assumptions behind the Capital Asset Pricing Model (CAPM) hold. Which of the following statements is true?

A.All stocks must have Sharpe ratios that are less than or equal to that of the market portfolio.

B.If you hold the market portfolio, adding or subtracting a little of any stock should give the same increase in expected return per unit of additional standard deviation as the Capital Market Line.

C.A stock with a negative Sharpe ratio must have a negative market beta.

D.All of the above.