Many Studies Measure Inequality with the 90-10, 50-10, or 90-50

Many studies measure inequality with the 90-10, 50-10, or 90-50 wage gaps rather than with the Gini coefficient. Why?

A) The Gini coefficient is poorly defined.
B) The Gini coefficient is ambiguous in terms of where in the earnings distribution inequality exists.
C) The Gini coefficient tends to jump around from one year to the next due to extreme outliers.
D) The Gini coefficient is a poor measure of international comparisons of inequality.
E) The Gini coefficient fails to take into account the entire wage distribution.