Using Gini Coefficient Measures Instead of the Ratio of Average

Using Gini coefficient measures instead of the ratio of average incomes in the world's richest country to the average income in the world's poorest country,Oatley concludes that

A) during the last 30 years global income inequality has begun to increase.
B) global inequality is much greater than domestic income inequality in even the most unequal countries.
C) global income inequality increased slowly but erratically between 1820 and 1970.
D) since 1980, the world's poorest societies have grown as fast as the richest countries.
E) between 1960 and 1980, the world's poorest societies grew faster than the world's richest.