Why does CLRM require that the covariance between X; and u; be 0? If the covariance is 0, then a change in X; does not affect u, and we can isolate the influence of X on Y O If the covariance is 0, then a change in X; affects u; and we can isolate the influence of X on Y O If the covariance is O, then a change in X; does not affect u; and we cannot isolate the influence of X on Y O None of the other options are correct