单选题 Some of the attendees at the technology convention were charged a ______ fee, as they were able to register as a group.

【正确答案】 C

【答案解析】[解析] 形容词词汇
根据上下文语义，此处意为“因为是团体注册所以享受了费用折扣”，所以应选形容词C. reduced(减少的)。A. final表示“最后的；决定性的”，B. total表示“总的”，D. costly表示“昂贵的”。