请教动名词加了the以后的用法

这几天在做prep的sc，发现一道题很奇怪

38. George Washington dedicated his life to the economic strengthening of the south with improvement of soil and diversification of corps.

A. the economic strengthening of the south with improvement of soil and diversification of corps.

B. strengthening the economy in the south with soil improvement and diversification of corps.

C. the strengthening the economy of the south through soil improvement and crop diversification.

D. the strengthening of the economy of the south through improving soil and crop diversifying

E. the economic strengthening in the south with improving soil and diversifying corp.

给出的答案是C。

我能理解考点是后面的soil improvement and crop diversification平行，但是the strengthening the economy这样的表述可以吗？

谢谢大家。

请大家帮忙看看呀