Correct Option: B

intermediary (N) : a person or organisation that helps other people/organisations to make an agreement by a means of communication between them; mediator
neutral (Adj.) : not supporting/ helping either side in a disagreement, competition, etc.; impartial; unbiased
judge (N.) : a person in a court who has the authority to decide how criminals should be punished or to make legal decisions; a person who decides who has won a competition; a person who has the necessary knowledge/ skills to give his opinion about the value or quality of somebody/ something
connoisseur (N.) : an expert on matters involving the judgement of beauty, quality or skill in art, food or music