Put the following steps of the model-building process in the order in which it would be statistically most appropriate to do them: (1) Estimate model. (1) Conduct hypothesis tests on coefficients. (11) Remove irrelevant variables. (1) Conduct diagnostic tests on the model residuals. O a. (l) then (lv) then (it) then (1) O b. (l) then (1) then (II) then (iv) Oc. (i) then (ii) then (iii) then (iv) O d.) then (iv) then (1) then (1)