GWD 第4套中的语法

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

答案E

不明白这里的what后面的部分作什么成分，多谢NN们指点 //bow

1. as
2. than
3. that
4. of what
5. at which

答案：D

不明白的是E为什么错呢？是因为没有charge sth. at price这样的搭配吗？

自己up一下:-)