What is the main idea of the first paragraph?

Câu hỏi: Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 35.
For more than six million American children, coming home after school means coming back to an empty house. Some deal with the situation by watching TV. Some may hide. But all of them have something in common. They spend part of each day alone. They are called "latchkey children". They are children who look after themselves while their parents work. And their bad condition has become a subject of concern.
Lynette Long was once the principal of an elementary school. She said, "We had a school rule against wearing jewelry. A lot of kids had chains around their necks with keys attached. I was constantly telling them to put the keys inside shirts. There were so many keys; it never came to my mind what they meant." Slowly, she learned that they were house keys.
She and her husband began talking to the children who had keys. They learned of the effect working couples and single parents were having on their children. Fear was the biggest problem faced by children at home alone. One in three latchkey children the Longs talked to reported being frightened. Many had nightmares and were worried about their own safety
The most common way latchkey children deal with their fears is by hiding. They may hide in a shower stall, under a bed or in a closet. The second is TV. They often turn the volume up. It's hard to get statistics on latchkey children, the Longs have learned. Most parents are slow to admit that they leave their children alone.
What is the main idea of the first paragraph?
A. Why kids hate going home
B. Children's activities at home
C. Bad condition of latchkey children
D. How kids spend free time