The story of Graffiti  is an interesting one. In the early 1970's, a New York City mailman used to travel across the city on the buses and subways to deliver his mail. He dreamt of riding on all the buses and subways in New York. His problem was that many buses and subways looked the same, so he would have to mark the buses and subways to know which one he had been on before. His name was Vic and his work ID was 156---so he left the mark VIC 156 on every journey he took. Soon people started to notice these sighs and wondered what they meant. When word got round what was happening, people would check the buses and subways to see if Vic had ridden on them. Other people decided they would take Vic's example and started leaving their own names. These marks became known as "Tags" .   Tags became more color1ful and artistic and gangs  of teenagers started leaving them on the walls in their neighborhood. This was to mark their area from other gangs. For many years people thought nothing of graffiti, but gradually they came to realize that graffiti was an art from that young people used to express themselves. So they gave them special area to paint on. But remember: If you paint on public walls, it is illegal  and you shouldn't do it. The author mainly wants to tell us   _  .
how Graffiti came onto being graffiti is an art form what graffiti is the story of a mailman
Question: The story of Graffiti  is an interesting one. In the early 1970's, a New York City mailman used to travel across the city on the buses and subways to deliver his mail. He dreamt of riding on all the buses and subways in New York. His problem was that many buses and subways looked the same, so he would have to mark the buses and subways to know which one he had been on before. His name was Vic and his work ID was 156---so he left the mark VIC 156 on every journey he took. Soon people started to notice these sighs and wondered what they meant. When word got round what was happening, people would check the buses and subways to see if Vic had ridden on them. Other people decided they would take Vic's example and started leaving their own names. These marks became known as "Tags" .   Tags became more color1ful and artistic and gangs  of teenagers started leaving them on the walls in their neighborhood. This was to mark their area from other gangs. For many years people thought nothing of graffiti, but gradually they came to realize that graffiti was an art from that young people used to express themselves. So they gave them special area to paint on. But remember: If you paint on public walls, it is illegal  and you shouldn't do it. The author mainly wants to tell us   _  .
A. how Graffiti came onto being
B. graffiti is an art form
C. what graffiti is
D. the story of a mailman
Answer: