Ralph would not concede that the work of the detectives was likely to be in vain given the price offered.
【正确答案】 D
【答案解析】解析：译文为：Ralph不愿承认，由于提供的价格，侦探们的工作很可能是徒劳的。concede承认。compromise让步，妥协；reconcile和解，调停；announce宣布；acknowledge承认，感谢。