16. In the 1970s, although the income of the black family increased greatly, the total black-white income gap was widened. Which of the following is the main factor contributing to this situation? ______

A、 More white families moved into high-paying jobs.
B、 Blacks had low positions and low pay in the work-place hierarchy.
C、 There were more children in black families.
D、 White families had more authority over others.

【正确答案】 B

【答案解析】 20世纪70年代，美国黑人的收入有了很大提高，但他们仍然受到歧视，受教育程度低，社会地位低，与白人的收入差距不降反增。选项B正确。