阅读下列短文，从每小题的三个选项中选出最佳选项。

    Tommy hates school and is always looking for excuse (借口) not to go. He spends more time at home than at school. On the days he has to (不得不) go to school, he looks for excuses to come home early.

    One day he comes home from school in the middle of day. His father is surprised, "You're home early, is the school closed (关闭的) today?"

    "No, Dad," Tommy says, "It's open. I came home early"

    "How can you do that? What do you say to the teacher?"

    "I told her that I had a new baby brother and that I had to come home and help you."

    "But your mother has had twins (双胞胎)," his father says, "you've got a baby brother and a baby sister."

    "Yes, I know, Dad," Tommy says," "I'm saving up my baby sister for (为..而储蓄) next week."