Passage TwoTom was aged four but

Passage Two
Tom was aged four but he was talking like a two-year-old baby. He was saying such things as "kick ball" and "want car", and using lots of one-word sentences. He should have been saying some really long sentences and telling stories with them. He wasn't. Something had gone terribly wrong.
Quite a few children have what is called a"language delay". For some reason they don't learn to speak as quickly as they should. Their friends shoot ahead and they're left behind. As a result, they get very lonely. Nobody wants to talk to you if you can't talk back.
Can anything be done to help these children? Yes. They can go to see a speech therapist—a person who's specially trained to work out what's wrong and who knows how to teach language to children. This is what happened to Tom. The speech therapist played some games with him and heard how he talked. She made a recording of his speech, and chatted to his mom and dad about his background. They'd taken Tom to see a doctor, but the doctor hadn't found anything wrong with him. He seemed perfectly normal in every way—except he just wasn't talking.
After Tom and his parents had gone home, the therapist listened carefully to the recording she'd made. Then she looked at a chart which showed how language developed in children aged two, three and four. She could see Tom was a long way behind.
The next step, she decided, was to teach Tom how to say some new sentences like"kick a red ball, " and"the clown is kicking a ball."Tom didn't get the new sentences right straight away. But the therapist was very patient, and after a few more visits he started to make some progress.
What can be inferred from the passage about "language delay"?
A、It can be prevented by doctors.
B、It is seldom found among children.
C、It can be improved with certain help.
D、It may result from hearing problems.
【正确答案】：C