He himself wrote the 20-page paper is the sentence which correctly uses a pronoun to create emphasis.
What is a Pronoun?
A pronoun is a word that is used instead of a noun or noun phrase. It refer to either a noun that has already been mentioned or to a noun that does not need to be named specifically. It is a word or a group of words that one may substitute for a noun or noun phrase. Some of the examples of pronouns are:- I, me, he, she, herself, you, it, that, they, each, few, many, who, whoever, whose, someone, everybody, etc.
Therefore, (B) option is the correct answer.
To learn more about pronouns, refer here :
https://brainly.com/question/26102308
#SPJ2
