Questions 14~16 are based on a talk about graffiti, an art form for some people or violence for others. You now have 15 seconds to read Questions 14~16. Why does the speaker cite the example of graffiti in the London undergroundA.To show that mindless graffiti can provoke violence.
B.To show that Londoners have a special liking for graffiti. C.To show that graffiti, in some cases, can constitute a crime. D.To show that graffiti can make the environment more colorful.