please explain why the other options are not correct as well thank you :)

According to the CAPM, for an individual asset j, the expected return is E(Rj)=Rf+j[E(RM)Rf] If all assets satisfy CAPM, which statement below is correct? a. If j is between 0 and 1 , then the expected return of this asset is between Rf and E[RM]. b. The above formula does not apply to the risk-free asset. c. We can measure j as the slope coefficient in a regression of asset j 's excess returns on the market excess returns. d. Two assets can have same expected returns but different beta