Answer :
The author’s purpose for inserting this sentence is:
"to undermine the significance of his critics’ letter"(Option B).
What is purpose in literature?
The purpose of a text usually is one of the following:
- To express one's creative abilities
- To Educate
- To Persuade etc.
The excerpt referred to above is from the letter of Dr. Martin Luther King's "Letter from Birmingham Jail."
Learn more about literary purpose at:
https://brainly.com/question/18533350
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