Answer with explanation in your own words and dont copy paste or make random guess.

What is the purpose of using autocovariance or autocorrelation of a time series? Select one: a. To measure the degree of linear dependence of a time series on its own past b. To eveluate the model spcification of a linear regression model c. To test for heteroskedasticity in a linear regression d. To measure the degree of multicollinearity in a linear regression