More than seven hundred years ago, the Prince of Wales had a very big and brave dog called Gelert. One day the Prince wanted to go hunting with his men. He told his dog to stay at home and look after his baby son. The baby was in a wooden cradle, which was like a small bed.When the Prince came back from hunting, Gelert ran out to meet his master. He wagged his tail and jumped up to put his paws on the Prince’s chest. Then the Prince saw the blood on Gelert’s jaws and head. “What have you done?” the Prince said. He rushed into his house and looked for his baby son. The cradle was lying on its side on the floor. The clothes were torn and there was blood on them. “So you have killed my son?” the Prince said angrily.” You unfaithful dog!” He took out his sword and killed the dog.Just as Gelert was dying, he managed to bark. Then the Prince heard a baby call to the dog. The prince ran out of the house and saw his son lying on the ground unhurt. Near him was a dead wolf. Then the Prince knew that Gelert had defended the baby and killed the wolf. Then Prince ran back into the house but he was too late. Gelert was dead. The Prince was very sad indeed. Tears ran down his face when he realized he had killed his faithful friend. The Prince carried the body of his brave dog to the top of a mountain and buried him there. After this, the Prince never smiled again. Every morning at dawn, he walked up the mountain and stood by the dog’s grave for a few minutes. If you go to Mount Snowdon inWales, people will show you where Gelert is buried. There is a sign by his grave. It reminds people of a brave and faithful dog.Choose the right answer:The Prince told the dog to _____________ when he was leaving.
选项：

A:take care of his baby at home ;
B:watch the door;
C:welcome his friends;
D:stop the strangers