Psychiatrist: While the first appearance of a phobia is usually preceded by a traumatizing event, not everyone who is traumatized by an event develops a phobia. Furthermore, many people with phobias have never been traumatized. These two considerations show that traumatizing events do not contribute to the occurrence of phobias.
The reasoning in the psychiatrist’s argument is most vulnerable to criticism on the grounds that the argument
T Events => Phobia
T Events => No Phobia
No T events => Phobia
Means T events don't contribute to phobia. The argument is saying that the relation of few T events with Phobia means nothing when establishing the relation because rest of both don't have any relation.
(A) treats the cause of the occurrence of a type of phenomenon as an effect of phenomena of that type
Treat cause as effect. T events as phobia? No
(B) presumes, without providing justification, that some psychological events have no causes that can be established by scientific investigation
Out of scope
(C) builds the conclusion drawn into the support cited for that conclusion
Conclusion into support. No this is not what happening here.
(D) takes for granted that a type of phenomenon contributes to the occurrence of another type of phenomenon only if phenomena of these two types are invariably associated
invariably means always. Looks like what we want.
(E) derives a causal connection from mere association when there is no independent evidence of causal connection
seems to say opposite of what argument is stating.
Hence D.