The sentence that best conveys the argument in "The Case for Shelter Animals" is:
People should rescue animals from pet stores.
This statement aligns with the advocacy for shelter animals and emphasizes the importance of choosing to adopt rather than buy from pet stores. However, it can also be argued that the first sentence about shelter pets becoming beloved family members supports the positive outcome of adopting shelter animals. If the primary focus of the argument is on the merits of adopting shelter animals, then that would be the best choice.