The correct option is A neither, nor
Correlative conjunctions are pairs of conjunctions that work together. Some examples are either/or, neither/nor, and not only/but also. The given sentence requires the use of correlative conjunctions. The combination neither/nor indicates that neither of the two choices can be selected. In other words, neither choice is available. Thus Option C is correct as neither/nor - When they're paired up they negate both parts of a statement. In the given sentence it is inferred that she is neither good nor bad. The option A can be ruled out as 'either'' is not followed by 'not' but by 'or'.While 'either' is used to offer a choice between two things,'not' is used to indicate negation. Option B can also be ruled out as 'neither' refers to 'not one and not the other' and 'or' indicates a choice. Both cannot be used together. Option D is discarded as 'than' introduces a comparison and is associated with comparatives and with words such as more, less, and fewer while 'neither' refers to 'not one and not the other'. If 'than' is to be used as a conjunction it must be followed by a clause with a subject and also optionally a verb.