Sentence Correction

The Chinatowns that were to develop as an increase in numbers of Chinese workers came to northern California and Hawaii in the rnid-1800s expanded the scale of Asian American communities.

A. were to develop as an increase in
B. were developing with the
C. developed as increases in
D. developed as increasing
E. developed with

A - incorrect, the use of the structure "were to develop" suggests that the action was supposed to take place but in fact it did not. Also "an increase in numbers ... came" is stylistically and logically incorrect. It is not the increase that came but the workers.
B - incorrect, the use of "with" suggests that a phrase should follow. However, there is a conjugated verb "came." Therefore, we need to use a clause.
C - incorrect, it is illogical and stylistically flawed. It is incorrect to say "increases in numbers of Chinese workers... came." It was the workers who came and not increases.
D - correct, it is correct to say that "increasing numbers of Chinese workers came ..."
E - incorrect, repeats the same mistake as answer B because there is the preposition "with" used.