下列说法，正确的是（ ）

A：对于函数，因为，所以函数在区间内必有零点

B：对于函数，因为，所以函数在区间    Of course mom was one of my strongest supporters. She worked behind the desk and even designed the room style. But with my mother’s support and encouragement, I never doubted we would succeed. Fifteen years later, we had the largest hotel system in the world — Holiday Inn. In 1979 my company had 1,759 inns in more than fifty countries with an income (收入) of $ 1 billion a year.
    You may not have started out life in the best situation. But if you can find a task in life worth working for and believe in yourself, nothing can stop you.