(A) Changes in the patient’s anxiety level during therapy can generally be used as an accurate measure of the extent to which the patient is becoming conscious of previously repressed beliefs.

The stimulus says that the occasions when patients become conscious of previously repressed beliefs are marked by decreased anxiety. They don’t say that the level of decrease varies directly or is correlated with the level of becoming conscious. Hence we cannot infer this from the stimulus.

(B) Even when one of a patient’s unconscious beliefs remains unconscious, researchers are sometimes able to discover this belief.

Not relevant to the given statements. Whether there are other mechanisms of identifying unconscious beliefs is out of scope.

(C) If psychoanalytic theory is correct, then most conscious beliefs originate as unconscious beliefs.

Again, not relevant. All we can say is that people can be made to express some unconscious beliefs through therapy. We cannot say that all conscious beliefs originate as unconscious.

(D) Researchers were able to distinguish expressed beliefs that had previously been unconscious from those that had long been conscious but that the patient had not previously expressed.

The given stimulus tells us that the researchers have been able to make people express their unconscious beliefs through therapy. A valid point here is – how do researchers know that the beliefs being expressed by the patients are unconscious beliefs and not merely conscious beliefs that the patients did not express previously? Since the stimulus says, “Researchers investigating repression observed occasions on which a patient undergoing therapy became aware of and expressed a previously unconscious belief” and we have to take the statement to be true, it means they were able to distinguish between unconscious beliefs and conscious but unexpressed beliefs. Hence (D) is the answer.

(E) Although the beliefs on which the mechanism of repression works are all unconscious, the operation of the mechanism itself is something of which patients are consciously aware.

Focus on the first part of this option. The statements in the stimulus tell us that repression keeps unconscious beliefs unconscious. They don’t tell us whether repression works on conscious beliefs or not – perhaps it keeps people from expressing conscious beliefs or perhaps it doesn’t work on conscious beliefs at all – the statements don’t say. We cannot say that the beliefs on which repression works are ALL unconscious. Hence we cannot infer this. Not the answer.

The correct answer is (D).