Answer:
the options are missing:
- A. the combination of changes in law and changes in social attitudes
- B. changes in production techniques made white workers unproductive
- C. a large decline in the average education levels for white workers
- D. a vast increase in the number of well-educated black workers
The answer is:
A. the combination of changes in law and changes in social attitudes
Around the mid 1900s, the earning gap between white males and black males fell, specially in the 1960s and 1970s, but since the 1980s it has remained stable. The Civil Rights Act of 1964 prohibited discrimination at work and a series of other regulations helped to narrow the earnings gap. The same applies to other minorities.
Sadly though, the earnings gap has remained stable for the last 40 years, and that hurts most minorities and women also. The earnings gap between women and men has decreased more since the 1980s, but in most industries women are still behind men even those who belong to minority groups.
Currently the earnings gap between white and black males is 26.5% on average, but on certain industries it is over 34%. Personally, I think that this is a type of hidden discrimination, because there is no reason why an employee should earn more or less based solely on his/her race, gender or culture.