Decide if you agree or disagree with each of the following statements and give a brief explanation of your decision:
(i) Like cross-sectional observations, we can assume that most time series observations are independently distributed.
(ii) The OLS estimator in a time series regression is unbiased under the first three Gauss-Markov assumptions.
(iii) A trending variable cannot be used as the dependent variable in multiple regression analysis.
(iv) Seasonality is not an issue when using annual time series observations.