article: Peter's uncle lived in the country. Once Peter went to stay with him for a few weeks. When they went for a walk or for a drive in the car and they passed somebody ,his uncle waved. Peter was surprised and said, "Uncle George, you know everybody here. Where did you meet them all?"
  "I don't know all these people," said his uncle
  "Then why do you wave to them?" asked Peter.
  "Well, Peter," answered his uncle, "when I wave to someone and he knows me, he is happy. He goes on his journey with a happier heart. But when I wave to some one and he doesn't know me, he is surprised and says to himself, 'Who is that man? Why did he wave to me?' So he has something to think about during the rest of his journey, and that makes his journey seem shorter. So I make everyone happy.
question: When Uncle George waved to his friends, they became   _  .
options: worried happy sad surprised