单选题 Trade unions often ______ with employers for better conditions of pay employment.

【正确答案】 C

【答案解析】句意：工会经常与老板谈判以期获得更高的报酬。bargain for讨价还价，谈判，指望。ask for请求，向…要。require需要，要求，为及物动词，后面不能接介词。plead for为…辩护。