This sentence is a correlative conjunction. Correlative conjunctions require the use of two words put in separate parts of the sentence for example, "whether/or", "either/or", "neither/nor", "not/but." So in the sentence "Either you must stop eating my food from the refrigerator or you must pay for it." The use of either and or make it correlative.
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.
The correct answer is b. Correlative. A correlative conjunction means that the conjunction used is more than one word, and that these words are related. In this case, the correlative conjunction is "either/or." You can tell they're related, because you can't have the sentence read correctly with just one of these words. Another example of a correlative conjunction would be the negative of this pair: neither/nor.