Of all the students of Grade Four, Bill is the tallest. He's thirteen, and of course, he's the oldest, too. But he's the worst student. He can't answer the easiest questions in class. And he never passes the exam. But the boy is the strongest in his school. Even the boys in higher grades are afraid of him. So every day he leaves home with an empty bag. When he gets to school, his bag will be full of fruit and cakes. Sometimes he brings some home. His mother, Mrs. King , is always happy when she sees them. She praises  her son, for she can save some money. This morning, Mrs. King went shopping in the market. She saw an old man selling eggs there. She chose twenty-four but paid only for twenty. The old man was too busy to count them. She went home quickly and told her husband as soon as he came back for lunch. "How clever you are!" Mr. King said happily. And Bill was busy eating the eggs, so he didn' t say a word. "What's your favorite food, dear?" asked Mr. King. "Eggs, of course." "Well, then, " said the man, "can you tell us what can lay eggs". The boy thought for a while and said, "Hens, ducks, geese...and...Mum!" "Oh? But why?" "I often hear my classmate call me 'Bad Egg'. " Choose the best answer.(,) Bill didn't say a word at table because  _  .
He was thinking of a problem He had to go to school on time He was afraid of his father He wanted to eat more eggs