Re: The uniformized set of characters, which some historians

The uniformized set of characters, which some historians date in the late Qing dynasty, was the key to the sustainability and prosperity of the Chinese culture over thousands of years.

(A) The uniformized set of characters, which some historians date

'Date in' is incorrect

(B) The uniformized set of characters, which some historians have thought to occur

The uniformized set of characters is not an occurence - Incorrect

(C) Uniformizing the set of characters, dated by some historians at

You cant date an action - Incorrect

(D) The uniformization of a set of characters, thought by some historians to have occured

Grammatically correct but the meaning goes for a toss IMO. Uniformizing "a"/some set of characters was key??? Keep anyways as the lesser of 5 evils

(E) The set of characters' uniformization, dated by some historians to have been

You cant date an event.. Incorrect

Ans D