But ______ with players, executives, and young people, I've learned that those who rise to the heights in any field aren't necessarily the ones with the greatest natural talent.
【正确答案】 C
【答案解析】解析：此空为句子状语部分，因主语和状语动作是主谓关系，故用现在分词作状语，同时分词动作发生在句子谓语动作之前，应该用现在分词的完成形式having worked。