请教，gwd20-29，奇怪的一道题

Q29:

A leading figure in the Scottish
                 enlightenment,  Adam Smith’s two major books are to democratic capitalism what Marx’s Das Kapital is to socialism.

1. Adam Smith’s two major books are to democratic capitalism what
2. Adam Smith’s two major books are to democratic capitalism like
3. Adam Smith’s two major books are to democratic capitalism just as
4. Adam Smith wrote two major books that are to democratic capitalism similar to
5. Adam Smith wrote two major books that are to democratic capitalism what

请问：答案是e，可是那个what起什么作用？怎么能连接两个名词呢？多谢

what Marx’s Das Kapital is to socialism, 这是一个名词性从句，相当于一个名词解释前面的democratic capitalism。也就是说他写的一本关于民族资本主义的书，其核心概念也就是马克思所谓的社会主义。

民主资本主义=社会主义

呵呵，看来资本主义确实是不可逾越的阶段啊，被一些人歪曲了快半个世纪。看看类似丹麦等北欧高福利国家，舒服得完全符合我们所描述的共产主义。

哦，那么先行词是资本主义，然后what是关系代词了？多谢了！

对于阁下的政治观点，我完全同意！