CD22 40语法再一问

The modernization program for the steel mill will cost approximately 51 million dollars, which it is hoped can be completed in the late 1980’s.

(A) The modernization program for the steel mill will cost approximately 51 million dollars, which it is hoped can be completed in the late 1980’s.

(B) The modernization program for the steel mill, hopefully completed in the late 1980’s, will cost approximately 51 million dollars.

(C) Modernizing the steel mill, hopefully to be completed in the late 1980’s, will cost approximately 51 million
                        dollars.

(D) The program for modernizing the steel mill, which can, it is hoped, be completed in the late 1980’s and cost approximately 51 million dollars.

(E) Modernizing the steel mill, a program that can, it is hoped, be completed in the late 1980’s, will cost approximately 51 million dollars. (The key)

My question is, what wrong with option C?

GMAT中一般不能出现有两个意思的词!

Thanks!