13 (A) Located in Germany, the school was unusual because it was a school for dogs instead of humans. (B) Though trained to be obedient, they are also taught that sometimes they must disobey the owner’s command. (C) The size, weight, preference, and nature of both are taken into account for a good match. (D) After a few years of trial-and-error, it was decided that certain breeds are better guides than others.