A、To preserve a tradition. B、To amuse her daughter. C、To help local education. D、To make some extra money. A短文中提到，玛利亚卖冰激凌并不是为了赚钱

There’s one sound that gets a big reaction from kids on a hot day, the sound of an ice-cream truck.
    Maria McCartney has been in the mobile ice-cream business since 2005.
     (16)"When I was a little girl, I saw an ice-cream truck and knew I wanted to have one someday," McCartney said.
    During the hot days of summer, Maria and her daughter drive an ice-cream truck through neighborhoods and parks in Billings.
    It’s not about making money for this former elementary school teacher. Rather,(17)she wants to preserve the tradition of the neighborhood ice-cream truck.
    " Truly my favorite part is to see the kids jumping up and down and they just get so excited. It’s great to build a memory for them too. There’s not a lot of these ice-cream trucks around anymore. The parents come out barefoot and screaming, ready to buy ice-cream: they remember when they were kids and they saw a truck," she said.
    While the treats may be ice cold, Maria has a warm heart for little faces.(18)Her truck features a donation bucket for kids who don’t have money for ice-cream.
    "When there are three kids and only two of them have money, I always make sure the third one gets something because I can’t drive away and have that third one not have something," she said.
Questions 16 to 18 are based on the passage you have just heard.
16. What does the speaker say about Maria McCartney?
17. Why does Maria go into the mobile ice-cream business?
18. Why does Maria put a donation bucket in her truck?