单选题 Doris's success lies in the fact ______ she is co-operative and eager to learn from others.
A. which B. that C. when D. why

【正确答案】 B
【答案解析】本题考查同位语从句。这是一个先行词是fact的同位语从句，只能用that连接。本题题意是：“多蕾丝的成功归功于她非常愿意与别人合作并且向别人学习。”