The correct piece of background knowledge is “People usually give their pets lots of attention”. By definition, a pet is an animal or bird that you keep in your home and look after. In order to support the inference that pets released into the wild will expect people to be friendly, one may take into account the previous definition and the background information that pets usually get lots of attention by its owner. A pet may expect love and care once released into the wild, since it may have received these before in a home.