单选题 He displayed a complete lack of courtesy and tact in dealing with his employer.

【正确答案】 C
【答案解析】句意:在同老板处理关系时,他毫无礼貌和头脑。courtesy礼貌,谦恭;civility礼貌,端庄;tenacity坚韧;curiosity好奇心;hostility敌意。