From the passage, we can learn that American people hold a (n) ______ attitude towards the upward trend of interracial birth.

A．The number of mixed-race couples decreased from 1970 to 1991.
B．There were more Chinese-white births than Chinese-Chinese births in 1989.
C．Mixed-race births remain a large proportion of all births in the United States.
D．The trend of mixed-race marriage is taking place among all racial and ethnic groups.

A．Most mixed births involve one white parent.
B．Between 1968 and 1989, children born to parents of different races increased.
C．Population Today is published by the Population Reference Bureau.
D．There were nearly 5,000 births in 1989.