A proper measure of economic progress of a country is

Gross domestic product
Net domestic product
Net national product
Per capita real income

The correct answer is D. Per capita real income.

Per capita real income is a measure of the average income of a country’s citizens, adjusted for inflation. It is calculated by dividing the country’s gross national income (GNI) by its population. GNI is the total value of all goods and services produced by a country’s residents in a year, plus income received from abroad, minus income paid to foreigners.

Per capita real income is a good measure of economic progress because it takes into account both the size of a country’s economy and the standard of living of its citizens. A country with a high per capita real income is likely to have a strong economy and a high standard of living.

A. Gross domestic product (GDP) is the total value of all goods and services produced within a country’s borders in a year. GDP is a good measure of the size of a country’s economy, but it does not take into account the distribution of income. A country with a high GDP may have a high standard of living for some of its citizens, but a low standard of living for others.

B. Net domestic product (NDP) is equal to GDP minus depreciation. Depreciation is the decrease in the value of capital goods over time. NDP is a better measure of economic progress than GDP because it takes into account the fact that capital goods wear out over time.

C. Net national product (NNP) is equal to NDP plus net income from abroad. Net income from abroad is the income that a country’s residents earn from investments abroad, minus the income that foreigners earn from investments in the country. NNP is a better measure of economic progress than NDP because it takes into account the income that a country’s residents earn from abroad.

In conclusion, the correct answer is D. Per capita real income. Per capita real income is a good measure of economic progress because it takes into account both the size of a country’s economy and the standard of living of its citizens.