D). He gives an example of two phrases that lost popularity with writers.
Explanation:
The authors provide a variety of evidence (factual or logical information, statistical data, etc.) to substantiate their claim and establish the credibility of their claim.
In the given excerpt, Orwell provides 'an illustration of two phrases 'explore every avenue' and 'leave no stone unturned' that lost popularity with writers'. This illustration reasonably backs his claim that 'Silly words and expressions often get disappeared not because of a specific evolutionary process but because of the conscious action of the minority' that assists the readers to accept and believe in his claim. Thus, <u>option D</u> is the correct answer.
