问题如下：
Noah Sota uses the CAPM to set CME. He estimates that one asset class has a beta of 0.8 in economic expansions and 1.2 in recessions. The expected return on the market is 12% in an expansion and 4% in a recession. The Rf is constant at 2%. Expansion and recession are equally likely.
Calculate the unconditional expected return and the conditional expectedreturns on the asset are
选项：
A. The conditional expected returns on the asset are 10% in an expansion,and 4.4% in a recession.
B. The conditional expected returns on the asset are 10% in an recession,and 4.4% in a expansion.
C. The unconditional expected return is 9.2%
解释：
A is correct
The conditional expected returns on the asset are 10% = 2% + 0.8 × (12% – 2%) in an expansion and 4.4% = 2% + 1.2 × (4% – 2%) in a recession.所以A正确，B不正确。
The unconditional expected return is 7.2% = [(0.5 × 10%) + (0.5 × 4.4%)].所以C选项不正确。
C 为什么不用加回Rf呢