While recognizing that lying often facilitates social ineractions,psychiatrists are seeking to determine when
they become destructive and which kinds of mental problems they can signall.
a.they become destructive and which kinds of mental problems they can signal
b.they become destructive and the mental problems that are signaled by them
c.it becomes destructive and what are the kinds of mental problems they signal
d.it becomes destructive and the mental problems that are signaled by it
e.it becomes destructive and which kinds of mental problems it can signal
As per the meaning of the sentence the lying should be the subject
In choices A and B they does not have clear antecedent also since lying is singular they does not makes sense in this context
same problem in choice C as well
D is a passive voice in its tone
So E is the best of the lot.