单选题 The firm's promise to increase our pay was a reluctant ______ to union demands, because the union would otherwise not go back to work.
A. response B. reply C. reaction D. concession

【正确答案】 D

【答案解析】response意为“答复，反应”，指一种有机体或机制对特定刺激的反应；reply意为“回答，答复”，指用言语或书写的回复；reaction意为“反应”，指对刺激的回应；concession意为“让步”，指开始坚持而后来又放弃的事物。根据空格后面的 would otherwise not go back to work(不会回去上班)可知，应该选用concession。