The
answer is:
A.
Correlative
 
Conjuctions that are used in
pairs are called correlative conjunctions. In the sentence above, the
conjuction used is “either..” plus “…or”. They may be similar to coordinating
conjuctions since they join sentences but correlative conjuctions are used in
pairs.
<span> </span>
        
             
        
        
        
Answer:
A. 
Explanation:
Try taking it out of the sentence and see if it can "stand alone."
 
        
             
        
        
        
D and then if that doesn't work B. If you have anything else to ask me further about my answer (cause I have got to admit it is quite vague) just ask. 
Hope this helps :) x