27.  If leadership, at its most basic meaning, consists of getting things done through others, then persuasion is one of the leader's ______ tools, many executives have assumed that this tool is beyond their grasp, available only to the charismatic and the eloquent.
【正确答案】 D
【答案解析】 形近形容词辨析。fundamental“基本的，基础的”；rudimentary“初步的，基本的，未充分发育的”；elementary“入门阶段的，初步的，基础的”；essential除了指“本质的，基本的”外，还指“必要的，不可缺少的，最重要的”，强调一事物与另一事物的不可分割性。故答案为D。