The word "either" is a correlative. The answer is D. This is because a correlative conjunction connects two nouns and ideas that relates to each other. Either uses "or" so it connects two choices in one situation.
Swan symbolizes grace and beauty on many levels of love, music, and poetry.
The answer is A. By dependent marker do you mean dependent clause?
The sentence "Moreover, it is probably just as valuable or more valuable to us now, than it was in the ancient past".
