The following can be used to calculate the expected return in event studies: O a. estimating the market model over the event window O b. all of the answers are correct O c.assuming the expected return equal zero O d. using the average returns over the event window If the errors are heteroscedastic, OLS estimators will be a. unbiased and consistent b. unbiased and best linear c. unbiased, consistent and best linear O d. consistent and best linear Clear my choice