Which is correct and most complete?

a. As is usual in DOE recommendations, they should recommend the settings corresponding to the best run in their DOE.

b. If RSM was applied to computer simulations, errors from the DOE modeling process and the simulation could cause poor real world confirmation results.

c. Before testing, selecting a range of factor settings that contain good values inside places less demand on expert judgment than directly selecting the final settings.

d. It is possible that no feasible snap tab design could be found from the analysis.

e. All of the above are correct.

f. All of the above are correct except

(a) and (e).