[求助]刘易斯语法笔记174题

求助这一题的正确答案：

According to a 1996 study published in the Journal of Human Resources. Americans of Middle Eastern descent were twice as likely __as was the national average to be self-employed.

A. as was the national average to be self-employed

B.as the average American to be self-employed

C.as the national average that the would be self-employed

D.to be self-employed than was the average American

E.that they would be self-employed than was the national average