The correct answer is (b) Per capita income.
Per capita income is a measure of the average income earned by each person in a country. It is calculated by dividing the total income of a country by its population. Per capita income is often used as a measure of the standard of living in a country. A higher per capita income indicates that people in a country are generally earning more money and have a higher standard of living.
Poverty ratio is the percentage of the population that lives below the poverty line. The poverty line is a measure of the minimum income necessary to meet basic needs such as food, clothing, and shelter. A higher poverty ratio indicates that more people in a country are struggling to meet their basic needs.
National income is the total income earned by all people in a country. It is calculated by adding up the incomes of all individuals, businesses, and governments in a country. National income is a measure of the size of the economy, but it does not take into account how the income is distributed.
Unemployment rate is the percentage of the labor force that is unemployed. The labor force is the total number of people who are either employed or actively looking for work. An unemployment rate indicates that there are people who are willing and able to work but cannot find jobs.
In conclusion, per capita income is the best measure of the standard of living in a country. It is a measure of the average income earned by each person in a country, and it takes into account the size of the population.