【单选题】

听力原文： According to a Justice Department report released in July 2003, the U. S. prison population surpassed 2 million for the first time-2,166,260 people were incarcerated in prisons or jails at the end of 2002 (the latest statistics available). Since 1990, the U. S. prison population, already the world's largest, has almost doubled.

About two -thirds of prisoners were in state and federal prisons, while the rest were in local jails. The report does not count all juvenile offenders, but noted that there were more than 10,000 inmates under age 18 held in adult prisons and jails in 2002. The number of women in federal and state prisons reached 97,491.
About 10. 4% of the entire African American male population in the United States aged 25 to 29 was incarcerated, by far the largest racial or ethnic group-by comparison, 2.4% of Hispanic men and 1.2% of white men in that same age group were incarcerated. According to a report by the Justice Policy Institute in 2002, the number of black men in prison has grown to five times the rate it was twenty years ago. Today, more African-American men are in jail than in college. In 2000 there were 791,600 black men in prison and 603,032 enrolled in college. In 1980, there were 143,000 black men in prison and 463,700 enrolled in college.
(33)
A．it has dropped in numbers.
B．it has tripled.
C．it has doubled.
D．it has become mostly Hispanic.