Our son, Ted, ___ use a new car because his old car is always breaking down on him.So,we're going to buy him a brand-new car for his birthday.

1.will have
2.could
3.could have
4.wouldn't have ​

could

выражение "could use something" значит, что кто-то в чём-то нуждается

В данном случае Ted нуждается  в новой машине