The best measure of economic development is C. Increase in per capita real gross national product.
Gross national income (GNI) is the total market value of all final goods and services produced by an economy in a given year, plus net income from abroad. It is a broad measure of a country’s economic activity.
Poverty ratio is the percentage of the population living below the poverty line. It is a measure of the extent of economic inequality in a country.
Increase in per capita real gross national product (GDP) is the increase in the value of goods and services produced by an economy per person, adjusted for inflation. It is a measure of the standard of living in a country.
Accelerated capital formation is the increase in the amount of capital goods, such as machinery and equipment, in an economy. It is a measure of the investment in an economy.
Of these four options, increase in per capita real GDP is the best measure of economic development because it takes into account both the size of the economy and the standard of living of the people.