How do you determine the main idea of a text

For english i have to find 4 errors in each diary post

Which most closely describes the author's use of historical information for the novel white fang? consider both texts provided. the author included details and descriptions of the dogs that match the historical details provided. b) the author changed the historical facts about early sled dogs to fit the needs of his plot and setting. c) the author changed the description and age of the dogs, which was necessary for his main character to develop bonds with the dogs. d) the author included historically accurate details of the dogs' working conditions, but the dogs he describes in his story are alaskan huskies.

What inference can you make about the narrator's point of view toward sudbury academy?