By using R studio R commands Thank you

Below is the file capm4.csv

I want to know b,c,d !! except a !!!

Plz comment with R code

a) Explain why the econometric model above is a simple regression model like those discussed in this chapter. (b) In the data file capm4.dat are data on the monthly returns of six firms (Microsoft, GE, GM. IBM. Disney, and Mobil-Exxon), the rate of return on the market portfolio (MKT), and the rate of return on the risk free asset (RISKFREE). The 132 observations cover January 1998 to December 2008. Estimate the CAPM model for each firm, and comment on their estimated beta values. Which firm appears most aggressive? Which firm appears most defensive? (c) Finance theory says that the intercept parameter ay should be zero. Does this stock, plot the fitted seem correct given your estimates? For the Micro regression line along with the data scatter. (d) Estimate the model for each firm under the assumption that 0. Do the estimates of the beta values change much