Income inequalities in a country can be measured by

Lorenz curve
Gini coefficient
Proportion of income received by different size groups
All of the above

The correct answer is: D. All of the above

A Lorenz curve is a graphical representation of the distribution of income or wealth. It shows the cumulative percentage of income or wealth that is received by the bottom x% of households, where x goes from 0 to 100. The Lorenz curve for a perfectly equal distribution would be a straight line from the bottom left corner to the top right corner, since everyone would receive the same amount of income or wealth. The more curved the Lorenz curve, the more unequal the distribution of income or wealth.

The Gini coefficient is a measure of the inequality of income distribution. It is calculated by taking the area between the Lorenz curve and the line of perfect equality, and dividing it by the total area under the line of perfect equality. The Gini coefficient ranges from 0 to 1, with 0 representing perfect equality and 1 representing perfect inequality.

The proportion of income received by different size groups is another way to measure income inequality. This measure is calculated by dividing the total income received by each group by the total population. The higher the proportion of income received by a small group of people, the more unequal the distribution of income.

All of these measures can be used to compare income inequality across countries or over time. They can also be used to track changes in income inequality within a country.