I am going with (D) on this one. Here's my train of thought:
People predict an action must be taken in order for a result to take place. When the result occurs after the action, they assume their prediction is correct (that it was casued by the action). The claim is that the result that takes place is not necessarily relatable to the action taken and is open to interpretation.
If I'm reading this correctly, then (D) is the only statement that supports the above claim, since it's saying that it is difficult or "often impossible" to determine the difference between a correct prediction / effective action and an incorrect prediction / ineffective action. As a result, what caused the result is open to interpretation, like the initial claim states.
My FA is (D).
Try rereading my posts with a British accent.