【单选题】

Questions 28 to 30 are based on the following news.At the end of the news item, you will be given 15 seconds to answer the questions.

Now, listen to the news.
Riot policeA．surrounded the Japanese embassy at once.
B．have encountered such protest for two years.
C．were armed with guns and clubs.
D．formed a human barricade to prevent possible violence.