How Might an Effective Manager Choose the Best Plan of Action

How might an effective manager choose the best plan of action when making a decision?

A) making a self-generated list of pros and cons and choosing based on the list
B) using the results of a survey that was sent to key customers who will be affected
C) sending a feedback form to customers after the plan has been executed
D) creating only one plan with no alternatives so it has to work
E) reviewing what other managers have done in the same situation and doing the same