Every weekday morning I take the 8:30 bus to go to my job. I know by sight several people who also ride in that bus. Some of the girls work as maids. They get off at each stop in ones, twos or threes. But at one corner something wonderful happens. Before the bus stops, a little dog races out of the nearest house. He doesn't look at two of the maids who get off. But for the third he has a joyful "Hello!" From head to tail his little body wags his happiness. Everyone on the bus watches until the maid and the dog go into the house. One day not long ago the maid wasn't on the bus. I wondered if the dog would be waiting for her. Sure enough, he was! He stood at the back door of the bus for a minute. I could see his joyful welcome turning into fearful worry. Where was she? The driver closed the back door. The dog ran to the front door. It, too, shut in his face. Everyone on the bus felt sad. Poor little pup! He looked so unhappy, standing there! The driver couldn't stand it. He opened the door and looked down at the dog. "She didn't come today," he said, in a loud, kind voice. A man in a front seat leaned forward. "Maybe she will come tomorrow," he called. The dog wagged his tail as if to say "thank you." He watched the bus as we pulled away. Then he turned to trot home -- alone. The next day everyone on the bus was happy to see the maid back again. Yes, the dog was waiting for her. The welcome he gave her was even warmer and more delighted than usual. We all smiled at one another. How bright and good the morning suddenly seemed to us! One day the maid wasn't on the bus and the dog   _  .
didn't appear stood waiting at the bus stop till we pulled away ran around looking for the maid went back as soon as he found the maid wasn't there
Question: Every weekday morning I take the 8:30 bus to go to my job. I know by sight several people who also ride in that bus. Some of the girls work as maids. They get off at each stop in ones, twos or threes. But at one corner something wonderful happens. Before the bus stops, a little dog races out of the nearest house. He doesn't look at two of the maids who get off. But for the third he has a joyful "Hello!" From head to tail his little body wags his happiness. Everyone on the bus watches until the maid and the dog go into the house. One day not long ago the maid wasn't on the bus. I wondered if the dog would be waiting for her. Sure enough, he was! He stood at the back door of the bus for a minute. I could see his joyful welcome turning into fearful worry. Where was she? The driver closed the back door. The dog ran to the front door. It, too, shut in his face. Everyone on the bus felt sad. Poor little pup! He looked so unhappy, standing there! The driver couldn't stand it. He opened the door and looked down at the dog. "She didn't come today," he said, in a loud, kind voice. A man in a front seat leaned forward. "Maybe she will come tomorrow," he called. The dog wagged his tail as if to say "thank you." He watched the bus as we pulled away. Then he turned to trot home -- alone. The next day everyone on the bus was happy to see the maid back again. Yes, the dog was waiting for her. The welcome he gave her was even warmer and more delighted than usual. We all smiled at one another. How bright and good the morning suddenly seemed to us! One day the maid wasn't on the bus and the dog   _  .
A. didn't appear
B. stood waiting at the bus stop till we pulled away
C. ran around looking for the maid
D. went back as soon as he found the maid wasn't there
Answer: