He is determined and competent and intelligent as well, which is it takes to become succe

网友回答

A. that; /
(答案→)B. what; a
C. what; /
D. that; a
解析：句意：他是有决心的，有能力的并且聪明的，凭借这些他成了一个成功人士。这里which引导的是定语从句，这里是句式it takes+宾语+to do，这里what引导的是表语从句，它在从句中做的是宾语；success指成功的人或事时，前面可以用不定冠词修饰，故选B。