The foot-in-the-door method is basically a psychological method where you ask for a small request first, then a bigger one later. So I think it's A, just because the others don't work. B is just straight up asking for a big favor, C is providing you with the "must-do" effect, and D is simply a favor for a favor.
B. But he stepped out briskly breathing deeply of the cold air
Answer:
The story takes place within the Yukon Domain, the region between north-western Canada and The frozen north, amid the Klondike gold surge. Jack London, in his callow a long time, was one of those who rolled the dice and went to the North to urge wealthy quick. Jack was a profoundly autonomous individual, and around the time of The Call of the Wild distribution, he “was surging with self-confidence” . Not as it were individuals were involved within the Klondike enterprise but moreover pooches just like the protagonist of the book. Buck may be a mixed-breed puppy; his father is St. Bernard, and his mother may be a Scotch shepherd dog. He lives in a sun-kissed Santa Clara Valley with his ace Judge Mill operator. Be that as it may, his quiet life closes when diggers within the North find a yellow metal called gold. Buck may be a strong animal who is not one or the other house nor pet hotel puppy, and he trusts the individuals he knows. In spite of the fact that he has never experienced people’s remorselessness, one day, the nursery worker Manuel, who may be a card shark, captures him and offers to pooch merchants.
Explanation:
No Explanation needed
A. To have peace and quiet
