When the U

When the U.S. Census Bureau calculates racial and ethnic composition, why might the population totals sometimes exceed 100 percent?

A) Since the year 2000, the U.S. Census Bureau has been forced to guess the population levels due to the rapid rise of illegal immigration.
B) Since 1950, researchers have received less funding to conduct surveys about race and ethnicity.
C) In the past 30 years, more people have been refusing to participate in the U.S. Census surveys.
D) Since the year 2000, respondents have been allowed to identify as more than one racial-ethnic category on the U.S. Census.