Concept:Effective decision-making requires firmness and confidence after choosing a course of action, without being rigidly inflexible.Explanation:Option A shows indecisiveness and repeated changing of decisions.Option C indicates regret or lack of confidence in one’s decision.Option D is too extreme and rigid, leaving no room for rational adjustment.Option B reflects a balanced and decisive approach: once a decision is made, one should not keep changing it unnecessarily.Answer:B. Do not change it