(A) cause clinical depression, but they have not established what these abnormalities are or
(B) cause clinical depression, but they have not established either what these abnormalities are nor
(C) are the cause of clinical depression, but they have neither not established what these abnormalities are or
(D) are the cause of clinical depression, but they have not established either what these abnormalities are nor
(E) causes clinical depression, but they have not established what these abnormalities are nor
in this question we have 2 problems
1) subject -verb agreement
2) idiom error
correct idioms are
a) either x or y
b) neither x nor y
choice b , c and d are out due to this idiom error
choice e is out since abnormailities doesn't agree with singluar verb causes
so we are left with only where subject and verb agrees and we don't have any incorrect idioms also
so my choice is A