Regarding the following statements, which of these answers is correct? (i) a only; (ii) e only; (iii) a, b, d, and e; (iv) a, b, c, and d; (v) d only: (a) The regression model is unbiased if there is no systematic tendency to overpredict or underpredict the true value of the response or Y variable at given values of the predictor or X variables; (b) the model is said to be correctly specified if it includes all relevant X variables, along with any necessary data transformations or interaction terms; (c) whereas underspecification of the model is a serious problem that leads to biased predictions, there are no consequences for overspecification, that is, including redundant and/or irrelevant variables; (d) the stepwise regression procedure is superior to the backward elimination or the forward selection versions because it can remove a previously added variable if a newly added variable supersedes the existing variable; (e) subsets regression is superior to all the stepwise methods because it examines all possible combinations of variables, rather than the one-variable-at-a-time approach of stepwise regression.