In practice, how do financial analysts estimate the beta of a publicly traded stock?

Group of answer choices

a. Regress the stock's returns on S&P 500 index's returns, and the slope of the regression line is the stock's beta.

b. Regress the stock's returns on S&P 500 index's returns, and the intercept of the regression line is the stock's beta.

c. The yield to maturity of Treasury securities can be used as the stock's beta.

d. The expected return of the S&P 500 index can be used the stock's beta.