Q:Read the following article and select the best answer. Article: It was Sunday morning. A butcher heard the doorbell and thought it must be a customer. But he was surprised to see that a dog was coming into his shop. The dog had $10 and a note in its mouth. The butcher took the note and read it. It said,"10 pork chops , please."So the butcher took the money and put a bag of chops in the dog's mouth. Then he quickly closed the shop because he decided to follow the dog. He found the dog on the street. The dog was waiting for a green light. Then the dog walked across the road. The dog went to a bus stop. When a bus arrived, the dog checked the number and then got on the bus. After a while, the dog stood up on his back paws to push the "stop" button . The bus stopped and the dog got off. Then the butcher followed it to get off the bus. The dog ran to a house and dropped the bag in front of the front door. It then began to beat its head against the front door. After a while, a big man opened the door and began shouting at the dog. The butcher ran up and shouted at the man, "What are you doing? Your dog is a genius ." The owner of the dog said, "Genius? No way! I always tell him to take the keys when he goes to the stores. But he never listens to me!" Question: Who was the customer that Sunday morning? - A big man. - A butcher. - A dog. - A little boy.
A:
A dog.