请教大全里的一道题

When people predict that certain result will not take place unless a certain action is taken, they believe that they have learned that the prediction is correct when the action is taken and the result occurs. On reflection, however, it often becomes clear that the result admits of more than one interpretation.

Which of the following, if true, best supports the claims above?

(A) Judging the success of an action requires specifying the goal of the action.

(B) Judging which action to take after a prediction is made requires knowing about other actions that have been successful in similar past situations.

(C) Learning whether a certain predictive strategy is good requires knowing the result using that strategy through several trials.

(D) Distinguishing a correct prediction and effective action from an incorrect prediction and ineffective action is often impossible.

(E) Making a successful prediction requires knowing the facts about the context of that prediction.

不理解怎么是D.