FRM一级模拟自测:An analyst is trying to get

An analyst is trying to get some insight into the relationship between the return on stock LMD (RLMD,t) and the return on the S&P 500 index (RS&P,t). Using historical data, the analyst estimates the following:
Annual mean return for LMD: 11%
Annual mean return for S&P 500 index: 7%
Annual volatility for S&P 500 index: 18%
Covariance between the returns of LMD and S&P 500 index: 6%
Assuming the analyst uses the same data to estimate the regression model given by:
RLMD,t = α + βR S&P,t  +  εt
Using the ordinary least squares technique, which of the following models will the analyst obtain?
a.   RLMD,t  = -0.02 + 0.54RS&P,t   + εt
b.    RLMD,t  = -0.02 + 1.85RS&P,t  + εt
c. RLMD,t   = 0.04 + 0.54RS&P,t + εt 
d.    RLMD,t  = 0.04 + 1.85RS&P,t  εt