Answer:
A. to establish credibility, suggesting many want to hear his tale
Step-by-step explanation:
In the excerpt from "Treasure Island," by Robert Louis Stevenson, the narrator directs attention to the number of credited men who wish to read his story, such as Squire Trelawney and Dr Livesey, who have asked him "to write down the whole particulars about Treasure Island." Besides, the author creates interest by mentioning an undiscovered treasure and the arrival of a mysterious character in the narrator's life.